diff --git a/flag.go b/flag.go
index 93da9aa..905ae83 100644
--- a/flag.go
+++ b/flag.go
@@ -49,7 +49,7 @@ func (c *flagConfig) Init(opts ...config.Option) error {
 		if !ok {
 			continue
 		}
-		fn, fv, fd := getFlagOpts(tf)
+		fn, fd, fv := getFlagOpts(tf)
 
 		rcheck := true
 
diff --git a/flag_test.go b/flag_test.go
index 23769f9..0ae6ab3 100644
--- a/flag_test.go
+++ b/flag_test.go
@@ -18,12 +18,15 @@ func TestLoad(t *testing.T) {
 	os.Args = append(os.Args, "-time", time.RFC822)
 	os.Args = append(os.Args, "-metadata", "key=20")
 	type Config struct {
-		Broker   string         `flag:"name=broker,desc='description with, comma',default='127.0.0.1:9092'"`
-		Verbose  bool           `flag:"name=verbose,desc='verbose output',default='false'"`
-		Addr     []string       `flag:"name=addr,desc='addrs',default='127.0.0.1:9092'"`
-		Wait     time.Duration  `flag:"name=wait,desc='wait time',default='2s'"`
-		Time     time.Time      `flag:"name=time,desc='some time',default='02 Jan 06 15:04 MST'"`
-		Metadata map[string]int `flag:"name=metadata,desc='some meta',default=''"`
+		Broker         string         `flag:"name=broker,desc='description with, comma',default='127.0.0.1:9092'"`
+		Verbose        bool           `flag:"name=verbose,desc='verbose output',default='false'"`
+		Addr           []string       `flag:"name=addr,desc='addrs',default='127.0.0.1:9092'"`
+		Wait           time.Duration  `flag:"name=wait,desc='wait time',default='2s'"`
+		Time           time.Time      `flag:"name=time,desc='some time',default='02 Jan 06 15:04 MST'"`
+		Metadata       map[string]int `flag:"name=metadata,desc='some meta',default=''"`
+		WithoutDefault string         `flag:"name=without_default,desc='with'"`
+		WithoutDesc    string         `flag:"name=without_desc,default='without_default'"`
+		WithoutAll     string         `flag:"name=without_all"`
 	}
 
 	ctx := context.Background()
diff --git a/util.go b/util.go
index 221b53c..413eafa 100644
--- a/util.go
+++ b/util.go
@@ -105,7 +105,7 @@ func (c *flagConfig) flagMap(v reflect.Value, fn, fv, fd string) error {
 			delim = d
 		}
 	}
-	flag.Func(fn, fd, func(s string) error {
+	flag.Func(fn, fv, func(s string) error {
 		ps := strings.Split(s, delim)
 		if len(ps) == 0 {
 			return nil
@@ -172,7 +172,7 @@ func (c *flagConfig) flagDuration(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := time.ParseDuration(fd)
+	i, err := time.ParseDuration(fv)
 	if err != nil {
 		return err
 	}
@@ -185,7 +185,7 @@ func (c *flagConfig) flagBool(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := strconv.ParseBool(fd)
+	i, err := strconv.ParseBool(fv)
 	if err != nil {
 		return err
 	}
@@ -207,11 +207,11 @@ func (c *flagConfig) flagInt(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := strconv.ParseInt(fd, 10, 64)
+	i, err := strconv.ParseInt(fv, 10, 64)
 	if err != nil {
 		return err
 	}
-	flag.IntVar(nv, fn, int(i), fd)
+	flag.IntVar(nv, fn, int(i), fv)
 	return nil
 }
 
@@ -220,11 +220,11 @@ func (c *flagConfig) flagInt64(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := strconv.ParseInt(fd, 10, 64)
+	i, err := strconv.ParseInt(fv, 10, 64)
 	if err != nil {
 		return err
 	}
-	flag.Int64Var(nv, fn, int64(i), fd)
+	flag.Int64Var(nv, fn, int64(i), fv)
 	return nil
 }
 
@@ -233,11 +233,11 @@ func (c *flagConfig) flagUint(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := strconv.ParseUint(fd, 10, 64)
+	i, err := strconv.ParseUint(fv, 10, 64)
 	if err != nil {
 		return err
 	}
-	flag.UintVar(nv, fn, uint(i), fd)
+	flag.UintVar(nv, fn, uint(i), fv)
 	return nil
 }
 
@@ -246,11 +246,11 @@ func (c *flagConfig) flagUint64(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := strconv.ParseUint(fd, 10, 64)
+	i, err := strconv.ParseUint(fv, 10, 64)
 	if err != nil {
 		return err
 	}
-	flag.Uint64Var(nv, fn, uint64(i), fd)
+	flag.Uint64Var(nv, fn, uint64(i), fv)
 	return nil
 }
 
@@ -259,11 +259,11 @@ func (c *flagConfig) flagFloat64(v reflect.Value, fn, fv, fd string) error {
 	if !ok {
 		return ErrInvalidValue
 	}
-	i, err := strconv.ParseFloat(fd, 64)
+	i, err := strconv.ParseFloat(fv, 64)
 	if err != nil {
 		return err
 	}
-	flag.Float64Var(nv, fn, float64(i), fd)
+	flag.Float64Var(nv, fn, float64(i), fv)
 	return nil
 }
 
@@ -295,7 +295,11 @@ func getFlagOpts(tf string) (string, string, string) {
 		}
 		ret[f] = p[1]
 	}
+
 	for idx := range ret {
+		if len(ret[idx]) == 0 {
+			continue
+		}
 		if ret[idx][0] == '\'' {
 			ret[idx] = ret[idx][1:]
 		}