diff --git a/export.go b/export.go
index 7ab4502..d6e7c57 100644
--- a/export.go
+++ b/export.go
@@ -76,14 +76,21 @@ func (c *Config) MapOnExists(key string, dst any) error {
 //
 //	dbInfo := Db{}
 //	config.Structure("db", &dbInfo)
-func (c *Config) Structure(key string, dst any) error {
+func (c *Config) Structure(key string, dst any) (err error) {
 	var data any
 	// binding all data on key is empty.
 	if key == "" {
-		// fix: if c.data is nil, directly return
+		// fix: if c.data is nil, don't need to apply map structure
 		if len(c.data) == 0 {
-			return nil
+			// init default value by tag: default
+			if c.opts.ParseDefault {
+				err = structs.InitDefaults(dst, func(opt *structs.InitOptions) {
+					opt.ParseEnv = c.opts.ParseEnv
+				})
+			}
+			return
 		}
+
 		data = c.data
 	} else {
 		// binding sub-data of the config
@@ -94,6 +101,7 @@ func (c *Config) Structure(key string, dst any) error {
 		}
 	}
 
+	// map structure from data
 	bindConf := c.opts.makeDecoderConfig()
 	// set result struct ptr
 	bindConf.Result = dst
diff --git a/go.mod b/go.mod
index ea19868..253bf40 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ require (
 	github.com/BurntSushi/toml v1.3.2
 	github.com/goccy/go-json v0.10.2
 	github.com/goccy/go-yaml v1.11.2
-	github.com/gookit/goutil v0.6.12
+	github.com/gookit/goutil v0.6.14
 	github.com/gookit/ini/v2 v2.2.2
 	github.com/gookit/properties v0.3.0
 	github.com/hashicorp/hcl v1.0.0
@@ -28,9 +28,9 @@ require (
 	github.com/mitchellh/go-wordwrap v1.0.1 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	github.com/zclconf/go-cty v1.13.0 // indirect
-	golang.org/x/sync v0.3.0 // indirect
-	golang.org/x/sys v0.10.0 // indirect
-	golang.org/x/term v0.10.0 // indirect
-	golang.org/x/text v0.11.0 // indirect
+	golang.org/x/sync v0.4.0 // indirect
+	golang.org/x/sys v0.13.0 // indirect
+	golang.org/x/term v0.13.0 // indirect
+	golang.org/x/text v0.13.0 // indirect
 	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect
 )
diff --git a/go.sum b/go.sum
index 1b295bb..0d71daa 100644
--- a/go.sum
+++ b/go.sum
@@ -22,8 +22,8 @@ github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/gookit/color v1.5.4 h1:FZmqs7XOyGgCAxmWyPslpiok1k05wmY3SJTytgvYFs0=
 github.com/gookit/color v1.5.4/go.mod h1:pZJOeOS8DM43rXbp4AZo1n9zCU2qjpcRko0b6/QJi9w=
-github.com/gookit/goutil v0.6.12 h1:73vPUcTtVGXbhSzBOFcnSB1aJl7Jq9np3RAE50yIDZc=
-github.com/gookit/goutil v0.6.12/go.mod h1:g6krlFib8xSe3G1h02IETowOtrUGpAmetT8IevDpvpM=
+github.com/gookit/goutil v0.6.14 h1:96elyOG4BvVoDaiT7vx1vHPrVyEtFfYlPPBODR0/FGQ=
+github.com/gookit/goutil v0.6.14/go.mod h1:YyDBddefmjS+mU2PDPgCcjVzTDM5WgExiDv5ZA/b8I8=
 github.com/gookit/ini/v2 v2.2.2 h1:3B8abZJrVH1vi/7TU4STuTBxdhiAq1ORSt6NJZCahaI=
 github.com/gookit/ini/v2 v2.2.2/go.mod h1:wGEfnBxv+7nVXytWM44tiqczv5hLKJ+m9MaA2uJg3iM=
 github.com/gookit/properties v0.3.0 h1:52NBYMOP5VXm3mKrQSdQoeEPgk2zXBGDF1R/xblsa6Y=
@@ -59,15 +59,15 @@ github.com/zclconf/go-cty v1.13.0 h1:It5dfKTTZHe9aeppbNOda3mN7Ag7sg6QkBNm6TkyFa0
 github.com/zclconf/go-cty v1.13.0/go.mod h1:YKQzy/7pZ7iq2jNFzy5go57xdxdWoLLpaEp4u238AE0=
 golang.org/x/crypto v0.7.0 h1:AvwMYaRytfdeVt3u6mLaxYtErKYjxA2OXjJ1HHq6t3A=
 golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561 h1:MDc5xs78ZrZr3HMQugiXOAkSZtfTpbJLDr/lwfgO53E=
-golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
-golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sync v0.4.0 h1:zxkM55ReGkDlKSM+Fu41A+zmbZuaPVbGMzvvdUPznYQ=
+golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
-golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.10.0 h1:3R7pNqamzBraeqj/Tj8qt1aQ2HpmlC+Cx/qL/7hn4/c=
-golang.org/x/term v0.10.0/go.mod h1:lpqdcUyK/oCiQxvxVrppt5ggO2KCZ5QblwqPnfZ6d5o=
-golang.org/x/text v0.11.0 h1:LAntKIrcmeSKERyiOh0XMV39LXS8IE9UL2yP7+f5ij4=
-golang.org/x/text v0.11.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.13.0 h1:bb+I9cTfFazGW51MZqBVmZy7+JEJMouUHTUSKVQLBek=
+golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
+golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
+golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 h1:H2TDz8ibqkAF6YGhCdN3jS9O0/s90v0rJh3X/OLHEUk=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
diff --git a/load_test.go b/load_test.go
index 7662d6b..7f788e6 100644
--- a/load_test.go
+++ b/load_test.go
@@ -39,6 +39,7 @@ func TestDefaultLoad(t *testing.T) {
 	})
 	is.NotEmpty(Data())
 	is.NotEmpty(Keys())
+	is.Empty(Sub("not-exist"))
 	is.Nil(err)
 }
 
diff --git a/read.go b/read.go
index 246a294..449f045 100644
--- a/read.go
+++ b/read.go
@@ -99,6 +99,21 @@ func (c *Config) Data() map[string]any {
 	return c.data
 }
 
+// Sub return sub config data by key
+func Sub(key string) map[string]any { return dc.Sub(key) }
+
+// Sub get sub config data by key
+//
+// Note: will don't apply any options, like ParseEnv
+func (c *Config) Sub(key string) map[string]any {
+	if mp, ok := c.GetValue(key); ok {
+		if mmp, ok := mp.(map[string]any); ok {
+			return mmp
+		}
+	}
+	return nil
+}
+
 // Keys return all config data
 func Keys() []string { return dc.Keys() }