diff --git a/structs/init.go b/structs/init.go
index 7999b857e..73aec3819 100644
--- a/structs/init.go
+++ b/structs/init.go
@@ -99,6 +99,21 @@ func initDefaults(rv reflect.Value, opt *InitOptions) error {
 						return err
 					}
 				}
+			} else if fv.Kind() == reflect.Slice {
+				el := sf.Type.Elem()
+				if el.Kind() == reflect.Pointer {
+					el = el.Elem()
+				}
+
+				// init sub struct in slice. like `[]SubStruct` or `[]*SubStruct`
+				if el.Kind() == reflect.Struct && fv.Len() > 0 {
+					for i := 0; i < fv.Len(); i++ {
+						subFv := reflect.Indirect(fv.Index(i))
+						if err := initDefaults(subFv, opt); err != nil {
+							return err
+						}
+					}
+				}
 			}
 			continue
 		}
diff --git a/structs/init_test.go b/structs/init_test.go
index d93398031..b3bbbcf41 100644
--- a/structs/init_test.go
+++ b/structs/init_test.go
@@ -39,13 +39,27 @@ func TestInitDefaults(t *testing.T) {
 	assert.Eq(t, "", u1.city)
 	// dump.P(u1)
 	// fmt.Printf("%+v\n", u1)
+}
 
-	err = structs.InitDefaults([]string{"invalid"})
+func TestInitDefaults_error(t *testing.T) {
+	err := structs.InitDefaults([]string{"invalid"})
 	assert.ErrMsg(t, err, "must be provider an pointer value")
 
 	arr := []string{"invalid"}
 	err = structs.InitDefaults(&arr)
 	assert.ErrMsg(t, err, "must be provider an struct value")
+
+	type User struct {
+		Name string `default:"inhere"`
+		Age  int    `default:"abc"`
+	}
+
+	u := &User{}
+	err = structs.InitDefaults(u)
+	assert.ErrMsg(t, err, comdef.ErrConvType.Error())
+	assert.Eq(t, "inhere", u.Name)
+	assert.Eq(t, 0, u.Age)
+	// dump.P(u)
 }
 
 func TestInitDefaults_parseEnv(t *testing.T) {
@@ -197,6 +211,13 @@ func TestInitDefaults_initStructSlice(t *testing.T) {
 	assert.NoErr(t, err)
 	assert.NotEmpty(t, u1.Extra)
 	assert.Eq(t, "chengdu", u1.Extra[0].City)
+
+	// test for not empty slice struct field
+	u2 := &User1{Extra: []*ExtraDefault{{City: "sh"}}}
+	err = structs.Init(u2)
+	// dump.P(u2)
+	assert.NoErr(t, err)
+	assert.Eq(t, "sh", u2.Extra[0].City)
 }
 
 func TestInitDefaults_ptrField(t *testing.T) {