diff --git a/demo/12_function.yaml b/demo/12_function.yaml
index baabc135fe98ada1d8c3df6311abf50d98854163..e1df2a6961075ea34a5df717933c04a5f5e85d8b 100644
--- a/demo/12_function.yaml
+++ b/demo/12_function.yaml
@@ -13,12 +13,12 @@ fields:
     range: 10-20
     format: sha1
     prefix: "sha1: "          
-    postfix: " "          
+    postfix: " "
 
   - field: field_3_base64 
     range: 10-20
     format: base64
-    prefix: "base64: "          
+    prefix: "base64: "
     postfix: "\t"
 
   - field: field_4
@@ -30,3 +30,8 @@ fields:
     format: urlencode
     prefix: "urlencode: "          
     postfix: "\t"
+
+  - field: field_5_uuid
+    format: "uuid()"
+    prefix: "uuid: "
+    postfix: " "
\ No newline at end of file
diff --git a/demo/t.yaml b/demo/t.yaml
index 3c6e21e0adb036042aef207aeab5a77221d23702..a46eefd75fefba83e5ec0938ac888dad6abe06f7 100644
--- a/demo/t.yaml
+++ b/demo/t.yaml
@@ -5,12 +5,7 @@ author: zentao
 version: 1.0
 
 fields:
-  - field: length32_random_no_separator2
-    use: length32_random_no_separator
-    from: uuid.v1.yaml
-    postfix: " "
-
-  - field: length162
-    use: length16
-    from: uuid.v1.yaml
+  - field: f1
+    range: 0-9
+    loop: 2-4
     postfix: " "
diff --git a/go.mod b/go.mod
index e839c8371d478e7f479207198105dd89e86dbd1c..199f92afc2984c6fccd5ba08fe4acf9aef5962dc 100644
--- a/go.mod
+++ b/go.mod
@@ -41,6 +41,7 @@ require (
 	github.com/pierrec/lz4/v4 v4.1.3 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/robfig/cron/v3 v3.0.1
+	github.com/satori/go.uuid v1.2.0 // indirect
 	github.com/smartystreets/assertions v1.2.0 // indirect
 	github.com/smartystreets/goconvey v1.6.4 // indirect
 	github.com/stretchr/testify v1.7.0 // indirect
diff --git a/go.sum b/go.sum
index 0cb201c8bb8d0a9407b323bcbb0e243ec9682e12..485ba8b7f0cec02f0fc120227f24fe5d843db237 100644
--- a/go.sum
+++ b/go.sum
@@ -241,6 +241,7 @@ github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJ
 github.com/robfig/cron v1.2.0 h1:ZjScXvvxeQ63Dbyxy76Fj3AT3Ut0aKsyd2/tl3DTMuQ=
 github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
 github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
+github.com/satori/go.uuid v1.2.0 h1:0uYX9dsZ2yD7q2RtLRtPSdGDWzjeM3TbMJP9utgA0ww=
 github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdhQKdks0=
 github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
diff --git a/src/gen/generator.go b/src/gen/generator.go
index 32fb5b528d1a7f93e56fef85c1e912da8a023b1f..cd182f9383e6f9cf64bc5a9cd45d6a5d47d3c9af 100644
--- a/src/gen/generator.go
+++ b/src/gen/generator.go
@@ -242,7 +242,8 @@ func GenerateValuesForField(field *model.DefField) []string {
 	for {
 		// 2. random replacement
 		isRandomAndLoopEnd := !vari.ResLoading && //  ignore rand in resource
-			!(*field).ReferToAnotherYaml && (*field).IsRand && (*field).LoopIndex == (*field).LoopEnd
+			!(*field).ReferToAnotherYaml &&
+			(*field).IsRand && (*field).LoopIndex > (*field).LoopEnd
 		// isNotRandomAndValOver := !(*field).IsRand && indexOfRow >= len(fieldWithValues.Values)
 		if count >= vari.Total || count >= len(fieldWithValues.Values) || isRandomAndLoopEnd {
 			for _, v := range fieldWithValues.Values {
diff --git a/src/gen/list.go b/src/gen/list.go
index 327b200e113e346f486ee3f3d848ff0930fe9897..ac7d4731ed8d179d1c97d0f5dc64b1cdc3f3788a 100644
--- a/src/gen/list.go
+++ b/src/gen/list.go
@@ -36,7 +36,10 @@ func CreateListFieldValues(field *model.DefField, fieldValue *model.FieldWithVal
 func CreateFieldValuesFromList(field *model.DefField, fieldValue *model.FieldWithValues) {
 	rang := field.Range
 	if rang == "" {
-		fieldValue.Values = append(fieldValue.Values, "")
+		for i := 0; i < vari.Total; i++ {
+			fieldValue.Values = append(fieldValue.Values, "")
+		}
+
 		return
 	}
 
diff --git a/src/test/test.go b/src/test/test.go
index a813eed5a9ab4d35b3596c33fa8c085a7bccc4ef..7137187024f476622cd0dc0fd1eaf5cf4c263220 100644
--- a/src/test/test.go
+++ b/src/test/test.go
@@ -1,13 +1,17 @@
 package main
 
 import (
-	"encoding/base64"
-	"log"
-	"net/url"
+	"fmt"
+	uuid "github.com/satori/go.uuid"
 )
 
 func main() {
-	str := "http://baidu.com"
-	log.Println(base64.StdEncoding.EncodeToString([]byte(str)))
-	log.Println(url.QueryEscape(str))
+	u1 := uuid.NewV4()
+	fmt.Printf("UUIDv4: %s\n", u1)
+
+	u1 = uuid.NewV4()
+	fmt.Printf("UUIDv4: %s\n", u1)
+
+	u1 = uuid.NewV4()
+	fmt.Printf("UUIDv4: %s\n", u1)
 }
diff --git a/src/utils/string/string.go b/src/utils/string/string.go
index 2ab8fa628564e2b233e322bd38e5e007a31419f6..2de4b5fb65b96f74c7f42b97580441346cb308da 100644
--- a/src/utils/string/string.go
+++ b/src/utils/string/string.go
@@ -12,6 +12,7 @@ import (
 	"github.com/easysoft/zendata/src/model"
 	constant "github.com/easysoft/zendata/src/utils/const"
 	"github.com/mattn/go-runewidth"
+	uuid "github.com/satori/go.uuid"
 	"gopkg.in/yaml.v2"
 	"net/url"
 	"regexp"
@@ -128,6 +129,10 @@ func FormatStr(format string, val interface{}, precision int) (ret string, pass
 		ret = UrlEncode(str)
 		pass = true
 		return
+	} else if strings.Index(format, "uuid()") == 0 {
+		ret = uuid.NewV4().String()
+		pass = true
+		return
 	}
 
 	str := fmt.Sprintf(format, val)
diff --git a/tmp/cache/.data.db b/tmp/cache/.data.db
index 6d815095484a464c32b4a745f231a4d999ae6c27..d912c02df93a9b81b11f16f08fe012b7454f6d48 100644
Binary files a/tmp/cache/.data.db and b/tmp/cache/.data.db differ