diff --git a/asn.go b/asn.go
new file mode 100644
index 0000000..e2ae300
--- /dev/null
+++ b/asn.go
@@ -0,0 +1,106 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	"github.com/metacubex/meta-rules-converter/output/meta"
+	"github.com/metacubex/meta-rules-converter/output/sing"
+	"github.com/oschwald/maxminddb-golang"
+	"github.com/spf13/cobra"
+)
+
+type ASN struct {
+	AutonomousSystemNumber       uint   `maxminddb:"autonomous_system_number"`
+	AutonomousSystemOrganization string `maxminddb:"autonomous_system_organization"`
+}
+
+func init() {
+	commandASN.PersistentFlags().StringVarP(&inPath, "file", "f", "", "Input File Path")
+	commandASN.PersistentFlags().StringVarP(&outType, "type", "t", "", "Output Type")
+	commandASN.PersistentFlags().StringVarP(&outDir, "out", "o", "", "Output Path")
+	mainCommand.AddCommand(commandASN)
+}
+
+var commandASN = &cobra.Command{
+	Use:  "asn",
+	RunE: convertASN,
+}
+
+func convertASN(cmd *cobra.Command, args []string) error {
+	if inPath == "" {
+		inPath = "GeoLite2-ASN.mmdb"
+	}
+	if outDir == "" {
+		outDir = "asn"
+	}
+	if outType == "" {
+		outType = "clash"
+	}
+	outDir = strings.TrimSuffix(outDir, "/")
+	db, err := maxminddb.Open(inPath)
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+
+	os.MkdirAll(outDir, 0755)
+
+	countryCIDRs := make(map[uint][]string)
+	networks := db.Networks(maxminddb.SkipAliasedNetworks)
+
+	for networks.Next() {
+		var asn ASN
+		network, err := networks.Network(&asn)
+		if err != nil {
+			fmt.Printf("Error decoding network: %v", err)
+			continue
+		}
+		countryCIDRs[asn.AutonomousSystemNumber] = append(countryCIDRs[asn.AutonomousSystemNumber], network.String())
+	}
+
+	var wg sync.WaitGroup
+	semaphore := make(chan struct{}, 100)
+
+	switch outType {
+	case "clash":
+		for number, cidrs := range countryCIDRs {
+			wg.Add(1)
+			semaphore <- struct{}{}
+			go func(number uint, cidrs []string) {
+				defer wg.Done()
+				defer func() { <-semaphore }()
+				code := fmt.Sprintf("AS%d", number)
+
+				err := os.WriteFile(outDir+"/"+code+".list", []byte(strings.Join(cidrs, "\n")), 0755)
+				if err != nil {
+					fmt.Println(code, " output err: ", err)
+				}
+				err = meta.SaveMetaRuleSet([]byte(strings.Join(cidrs, "\n")), "ipcidr", "text", filepath.Join(outDir, code+".mrs"))
+				if err != nil {
+					fmt.Printf("%s output err: %v", code, err)
+				}
+			}(number, cidrs)
+		}
+	case "sing-box":
+		for number, cidrs := range countryCIDRs {
+			wg.Add(1)
+			semaphore <- struct{}{}
+			go func(number uint, cidrs []string) {
+				defer wg.Done()
+				defer func() { <-semaphore }()
+				ipcidrRule := []sing.DefaultHeadlessRule{{IPCIDR: cidrs}}
+				err := sing.SaveSingRuleSet(ipcidrRule, filepath.Join(outDir, fmt.Sprintf("AS%d", number)))
+				if err != nil {
+					fmt.Printf("AS%d output err: %v", number, err)
+				}
+			}(number, cidrs)
+		}
+	}
+
+	wg.Wait()
+	return nil
+}