diff --git a/django_rest_sample/urls.py b/django_rest_sample/urls.py
index 05fb841da371ccc55cbe81f3dacc6687bba81312..606b35101976ef18a829f6d03d35f81876f293f5 100644
--- a/django_rest_sample/urls.py
+++ b/django_rest_sample/urls.py
@@ -16,6 +16,7 @@ Including another URLconf
 from django.contrib import admin
 from django.urls import path
 from rest_framework import routers
+from django.urls import include, path
 
 from library_app.views import BookViewSet, CategoryViewSet, AuthorViewSet
 
@@ -26,5 +27,6 @@ router.register(r'authors', AuthorViewSet)
 urlpatterns = router.urls
 
 urlpatterns += [
+    path('library_app/', include('library_app.urls')),
     path('admin/', admin.site.urls),
 ]
diff --git a/library_app/selfFunc.py b/library_app/selfFunc.py
new file mode 100644
index 0000000000000000000000000000000000000000..d308ca515d448e2a9b0f5c843c3187f819f23b11
--- /dev/null
+++ b/library_app/selfFunc.py
@@ -0,0 +1,85 @@
+#return the Book queryset object
+def getBookObject(bookClass):
+    return bookClass.queryset
+
+##return the author queryset object
+def getAuthorObject(authorClass):
+    return authorClass.queryset
+
+#return the category queryset object
+def getCategoryObject(categoryClass):
+    return categoryClass.queryset
+
+#use the build-in function to count the number of return object directly
+def countBook(bookObject):
+    """
+    input: the book queryset object
+    return: number of book
+    """
+    return bookObject.count()
+
+def totalValue(bookObject):
+    """
+    input: the book queryset object
+    output: the total value of book 
+    """
+    #get the book's price list
+    valueList = bookObject.values('price')
+    #initialize
+    value = 0
+    #traverse the price list and sum up
+    for i in range(len(valueList)):
+        value += valueList[i]['price']
+    return value
+
+#get the authod whose number of book is the most
+def authorMostbook(bookObject, authorObject):
+    """
+    input: book queryset object, author queryset object
+    output: author name and number of book
+    """
+    #use a dict to store the infor, key is author id, value is the count of frequency of author id 
+    countDict = {}
+    #the author list of book
+    bookList = bookObject.values('author')
+    #traverse the list
+    #if the author is not in dict, add it into dict and set the value as 1
+    #if the author is already in dict, get the value and add 1 
+    for i in range(len(bookList)):
+        if(bookList[i]['author'] not in countDict):
+            countDict[bookList[i]['author']] = 1
+        else:
+            count = countDict[bookList[i]['author']]
+            countDict[bookList[i]['author']] = count + 1
+    #zip the keys list and values list
+    #use max() to get the biggest value and the corresponding author id
+    key, value = max(zip(countDict.keys(),countDict.values()))
+    #get the author name according to the id
+    authorName = authorObject.values().filter(id=key)[0]['name']
+    return authorName, value
+
+def categoryMostBook(bookObject, categoryObject):
+    """
+    input: book queryset object, catrgory queryset object
+    output: category title and the number of book in that category 
+    """
+    #use dict to store the infor
+    countDict = {}
+    #get the list of category id from book queryset object
+    bookList = bookObject.values('category_id')
+    #traverse the list
+    #if the category id is not in dict, add it into dict and set the value as 1
+    #if the category id is already in dict, get the value and add 1 
+    for i in range(len(bookList)):
+        if(bookList[i]['category_id'] not in countDict):
+            countDict[bookList[i]['category_id']] = 1
+        else:
+            count = countDict[bookList[i]['category_id']]
+            countDict[bookList[i]['category_id']] = count + 1 
+    #zip the keys list and values list
+    #use max() to get the biggest value and the corresponding category id
+    key, value = max(zip(countDict.keys(),countDict.values()))
+    #get the category name
+    category = categoryObject.values().filter(id=key)[0]['title'] 
+
+    return category, value 
\ No newline at end of file
diff --git a/library_app/serializers.py b/library_app/serializers.py
index 849aea1f7cfdf51d36afe7743319ac57b0688bc5..9b79f72ac7c920cfd472ab25c220ac30ec49e303 100644
--- a/library_app/serializers.py
+++ b/library_app/serializers.py
@@ -9,6 +9,12 @@ class AuthorSerializer(serializers.ModelSerializer):
         model = Author
         fields = "__all__"
 
+class CategorySerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Category
+        fields = "__all__"
+
+
 class BookReadSerializer(serializers.ModelSerializer):
     category = CategorySerializer()
     author = AuthorSerializer()
@@ -22,7 +28,3 @@ class BookWriteSerializer(serializers.ModelSerializer):
         model = Book
         fields = "__all__"
 
-class CategorySerializer(serializers.ModelSerializer):
-    class Meta:
-        model = Category
-        fields = "__all__"
diff --git a/library_app/templates/.keep b/library_app/templates/.keep
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/library_app/templates/library_app/.keep b/library_app/templates/library_app/.keep
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/library_app/templates/library_app/index.html b/library_app/templates/library_app/index.html
new file mode 100644
index 0000000000000000000000000000000000000000..9061f5ae26bfff9d4d7dc1177944fdc4a542ec78
--- /dev/null
+++ b/library_app/templates/library_app/index.html
@@ -0,0 +1,4 @@
+<h1>Number of book: {{ numBook|safe }}</h1>
+<h2>Total cost of all Book: {{ value|safe }}</h2>
+<h2>The author {{author|safe}} has the most number of book of {{count|safe}}</h2>
+<h2>The category {{category|safe}} has the most number of book of {{countCategory|safe}}</h2>
diff --git a/library_app/urls.py b/library_app/urls.py
new file mode 100644
index 0000000000000000000000000000000000000000..3ef24d9717f6abdd8d356990d19b5c92b2ed0261
--- /dev/null
+++ b/library_app/urls.py
@@ -0,0 +1,7 @@
+from django.urls import path
+
+from . import views
+
+urlpatterns = [
+    path('', views.index, name='index'),
+]
\ No newline at end of file
diff --git a/library_app/views.py b/library_app/views.py
index da56ab7fe376dc3d778ee7e3d280b4971270631d..f6d634c1c8615aeb8c202599f2f642558b3f0a5f 100644
--- a/library_app/views.py
+++ b/library_app/views.py
@@ -2,11 +2,13 @@ from rest_framework import viewsets
 
 from library_app.models import Category, Author, Book
 from library_app.serializers import CategorySerializer, AuthorSerializer, BookReadSerializer, BookWriteSerializer
+from django.http import HttpResponse
+from django.shortcuts import render
 
+from .selfFunc import *
 
 class BookViewSet(viewsets.ModelViewSet):
     queryset = Book.objects.all()
-
     def get_serializer_class(self):
         if self.request.method in ['GET', 'HEAD']:
             return BookReadSerializer
@@ -21,3 +23,33 @@ class CategoryViewSet(viewsets.ModelViewSet):
 class AuthorViewSet(viewsets.ModelViewSet):
     queryset = Author.objects.all()
     serializer_class = AuthorSerializer
+
+def index(request):
+    """
+    go to the site: http://localhost:8000/library_app/
+    ALL the function are implemented in the doc selfFunc.py
+    """
+    book = BookViewSet()
+    bookObject = getBookObject(book)
+
+    author = AuthorViewSet()
+    authorObject = getAuthorObject(author)
+
+    category = CategoryViewSet 
+    categoryObject = getCategoryObject(category)
+
+    #number of book
+    numBook = countBook(bookObject)
+    #value:
+    value = totalValue(bookObject)
+    #author with most book 
+    author, count = authorMostbook(bookObject, authorObject)
+    #category with most book
+    category, countCategory = categoryMostBook(bookObject, categoryObject)
+
+
+
+
+    result = {'numBook': numBook, 'value': value, 'author': author, 'count': count, 
+    'category': category, "countCategory": countCategory}
+    return render(request,'library_app/index.html', result)
\ No newline at end of file
diff --git "a/\345\274\200\345\217\221\347\254\224\350\256\260.md" "b/\345\274\200\345\217\221\347\254\224\350\256\260.md"
new file mode 100644
index 0000000000000000000000000000000000000000..acfd112c0443244253dfaf6ecfa00f1f7d63c7e9
--- /dev/null
+++ "b/\345\274\200\345\217\221\347\254\224\350\256\260.md"
@@ -0,0 +1,52 @@
+所用方法都在文件selfFunc.py 中实现
+ 1. Total number of books owned.
+首先获取Book object, 
+
+```
+book = BookViewSet()
+bookObject = getBookObject(book)
+```
+然后对bookObject调用function countBook(bookObject)以获取总的书本数量；其实现方法为对bookObject调用内置函数count()，直接输出书的数量。
+
+  2. Total cost of all books.
+获取bookObject中说有书的价格
+
+```
+valueList = bookObject.values('price')
+```
+然后对于valueList，用for循环将所有价格相加，然后输出。
+
+```
+value = 0
+#traverse the price list and sum up
+for i in range(len(valueList)):
+    value += valueList[i]['price']
+```
+  3. Author with most books.
+思想：利用dict储存信息，遍历library中的所有书，如果遇到一个新的作者（作者id not in dict），建一个新的key，并将value设为1；如果作者已经在dict里（作者id in dict), 获取在字典中该作者的书的数量，并更新（dict[author id]）= value+1
+
+```
+for i in range(len(bookList)):
+    if(bookList[i]['author'] not in countDict):
+        countDict[bookList[i]['author']] = 1
+    else:
+        count = countDict[bookList[i]['author']]
+        countDict[bookList[i]['author']] = count + 1
+```
+然后获取字典中value最大的值和其对应的id
+获取id后，可以在authorObject中，通过filter(ID=id)获取作者名字
+
+  4. Category with most books.
+思想：同 3. 相似。利用dict储存信息，遍历library中的所有书，如果遇到一个新的类别（category id not in dict），建一个新的key，并将value设为1；如果类别已经在dict里（category id in dict), 获取在字典中该类别的书的数量，并更新（dict[category id]）= value+1
+
+```
+ for i in range(len(bookList)):
+    if(bookList[i]['category_id'] not in countDict):
+        countDict[bookList[i]['category_id']] = 1
+    else:    
+        count = countDict[bookList[i]['category_id']]
+        countDict[bookList[i]['category_id']] = count + 1 
+```
+然后获取字典中value最大的值和其对应的id
+获取id后，可以在categoryObject中，通过filter(ID=id)获取作者名字
+