diff --git a/docs/docs.go b/docs/docs.go
index 24693e47..14a36c1e 100644
--- a/docs/docs.go
+++ b/docs/docs.go
@@ -5574,10 +5574,15 @@ const docTemplate = `{
         },
         "schema.AnswerAddReq": {
             "type": "object",
+            "required": [
+                "content"
+            ],
             "properties": {
                 "content": {
                     "description": "content",
-                    "type": "string"
+                    "type": "string",
+                    "maxLength": 65535,
+                    "minLength": 6
                 },
                 "html": {
                     "description": "html",
@@ -5591,10 +5596,15 @@ const docTemplate = `{
         },
         "schema.AnswerUpdateReq": {
             "type": "object",
+            "required": [
+                "content"
+            ],
             "properties": {
                 "content": {
                     "description": "content",
-                    "type": "string"
+                    "type": "string",
+                    "maxLength": 65535,
+                    "minLength": 6
                 },
                 "edit_summary": {
                     "description": "edit_summary",
diff --git a/docs/swagger.json b/docs/swagger.json
index fb2f297b..55e01da1 100644
--- a/docs/swagger.json
+++ b/docs/swagger.json
@@ -5562,10 +5562,15 @@
         },
         "schema.AnswerAddReq": {
             "type": "object",
+            "required": [
+                "content"
+            ],
             "properties": {
                 "content": {
                     "description": "content",
-                    "type": "string"
+                    "type": "string",
+                    "maxLength": 65535,
+                    "minLength": 6
                 },
                 "html": {
                     "description": "html",
@@ -5579,10 +5584,15 @@
         },
         "schema.AnswerUpdateReq": {
             "type": "object",
+            "required": [
+                "content"
+            ],
             "properties": {
                 "content": {
                     "description": "content",
-                    "type": "string"
+                    "type": "string",
+                    "maxLength": 65535,
+                    "minLength": 6
                 },
                 "edit_summary": {
                     "description": "edit_summary",
diff --git a/docs/swagger.yaml b/docs/swagger.yaml
index fef405df..2dd68b72 100644
--- a/docs/swagger.yaml
+++ b/docs/swagger.yaml
@@ -218,6 +218,8 @@ definitions:
     properties:
       content:
         description: content
+        maxLength: 65535
+        minLength: 6
         type: string
       html:
         description: html
@@ -225,11 +227,15 @@ definitions:
       question_id:
         description: question_id
         type: string
+    required:
+    - content
     type: object
   schema.AnswerUpdateReq:
     properties:
       content:
         description: content
+        maxLength: 65535
+        minLength: 6
         type: string
       edit_summary:
         description: edit_summary
@@ -246,6 +252,8 @@ definitions:
       title:
         description: title
         type: string
+    required:
+    - content
     type: object
   schema.AvatarInfo:
     properties:
diff --git a/internal/schema/answer_schema.go b/internal/schema/answer_schema.go
index 724d9af9..34383eb4 100644
--- a/internal/schema/answer_schema.go
+++ b/internal/schema/answer_schema.go
@@ -20,10 +20,10 @@ const (
 )
 
 type AnswerAddReq struct {
-	QuestionID string `json:"question_id" ` // question_id
-	Content    string `json:"content" `     // content
-	HTML       string `json:"html" `        // html
-	UserID     string `json:"-" `           // user_id
+	QuestionID string `json:"question_id" `                                 // question_id
+	Content    string `validate:"required,gte=6,lte=65535" json:"content" ` // content
+	HTML       string `json:"html" `                                        // html
+	UserID     string `json:"-" `                                           // user_id
 }
 
 func (req *AnswerAddReq) Check() (errFields []*validator.FormErrorField, err error) {
@@ -32,13 +32,13 @@ func (req *AnswerAddReq) Check() (errFields []*validator.FormErrorField, err err
 }
 
 type AnswerUpdateReq struct {
-	ID           string `json:"id"`                                // id
-	QuestionID   string `json:"question_id" `                      // question_id
-	UserID       string `json:"-" `                                // user_id
-	Title        string `json:"title" `                            // title
-	Content      string `json:"content"`                           // content
-	HTML         string `json:"html" `                             // html
-	EditSummary  string `validate:"omitempty" json:"edit_summary"` // edit_summary
+	ID           string `json:"id"`                                          // id
+	QuestionID   string `json:"question_id" `                                // question_id
+	UserID       string `json:"-" `                                          // user_id
+	Title        string `json:"title" `                                      // title
+	Content      string `validate:"required,gte=6,lte=65535" json:"content"` // content
+	HTML         string `json:"html" `                                       // html
+	EditSummary  string `validate:"omitempty" json:"edit_summary"`           // edit_summary
 	NoNeedReview bool   `json:"-"`
 	// whether user can edit it
 	CanEdit bool `json:"-"`