diff --git a/x509/x509.go b/x509/x509.go
index ea92800a..cf314a61 100644
--- a/x509/x509.go
+++ b/x509/x509.go
@@ -614,8 +614,28 @@ var (
 	oidPublicKeyRSA   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
 	oidPublicKeyDSA   = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1}
 	oidPublicKeyECDSA = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
+	oidPublicKeySM2   = asn1.ObjectIdentifier{1, 2, 156, 10197, 1, 301}
 )
 
+func getPublicKeyAlgorithmFromAlgorithm(alg pkix.AlgorithmIdentifier) PublicKeyAlgorithm {
+	oid := alg.Algorithm
+	switch {
+	case oid.Equal(oidPublicKeyRSA):
+		return RSA
+	case oid.Equal(oidPublicKeyDSA):
+		return DSA
+	case oid.Equal(oidPublicKeyECDSA):
+		parameters := alg.Parameters
+		var sm2Oid = asn1.ObjectIdentifier{}
+		_, err := asn1.Unmarshal(parameters.FullBytes, &sm2Oid)
+		if err == nil && sm2Oid.Equal(oidPublicKeySM2) {
+			return SM2
+		}
+		return ECDSA
+	}
+	return UnknownPublicKeyAlgorithm
+}
+
 func getPublicKeyAlgorithmFromOID(oid asn1.ObjectIdentifier) PublicKeyAlgorithm {
 	switch {
 	case oid.Equal(oidPublicKeyRSA):
@@ -1260,7 +1280,7 @@ func parseCertificate(in *certificate) (*Certificate, error) {
 		getSignatureAlgorithmFromAI(in.TBSCertificate.SignatureAlgorithm)
 
 	out.PublicKeyAlgorithm =
-		getPublicKeyAlgorithmFromOID(in.TBSCertificate.PublicKey.Algorithm.Algorithm)
+		getPublicKeyAlgorithmFromAlgorithm(in.TBSCertificate.PublicKey.Algorithm)
 	var err error
 	out.PublicKey, err = parsePublicKey(out.PublicKeyAlgorithm, &in.TBSCertificate.PublicKey)
 	if err != nil {