diff --git a/plugin/kvm/src/main/java/org/zstack/kvm/KVMAgentCommands.java b/plugin/kvm/src/main/java/org/zstack/kvm/KVMAgentCommands.java
index 90e576cad7f..36c5d35ecde 100755
--- a/plugin/kvm/src/main/java/org/zstack/kvm/KVMAgentCommands.java
+++ b/plugin/kvm/src/main/java/org/zstack/kvm/KVMAgentCommands.java
@@ -2283,8 +2283,6 @@ public static class StartVmCmd extends vdiCmd implements VmAddOnsCmd {
         private boolean isApplianceVm;
         @GrayVersion(value = "5.0.0")
         private String systemSerialNumber;
-        @GrayVersion(value = "5.5.12")
-        private String guestOsType;
         @GrayVersion(value = "5.0.0")
         private String bootMode;
         // used when bootMode == 'UEFI'
@@ -2478,14 +2476,6 @@ public void setSystemSerialNumber(String systemSerialNumber) {
             this.systemSerialNumber = systemSerialNumber;
         }
 
-        public String getGuestOsType() {
-            return guestOsType;
-        }
-
-        public void setGuestOsType(String guestOsType) {
-            this.guestOsType = guestOsType;
-        }
-
         public String getVmCpuModel() {
             return vmCpuModel;
         }
diff --git a/plugin/kvm/src/main/java/org/zstack/kvm/KVMHost.java b/plugin/kvm/src/main/java/org/zstack/kvm/KVMHost.java
index 27ba23476ed..96c2bd7bfa5 100755
--- a/plugin/kvm/src/main/java/org/zstack/kvm/KVMHost.java
+++ b/plugin/kvm/src/main/java/org/zstack/kvm/KVMHost.java
@@ -4436,7 +4436,6 @@ protected void startVm(final VmInstanceSpec spec, final NeedReplyMessage msg, fi
         cmd.setAdditionalQmp(VmGlobalConfig.ADDITIONAL_QMP.value(Boolean.class));
         cmd.setApplianceVm(spec.getVmInventory().getType().equals("ApplianceVm"));
         cmd.setSystemSerialNumber(makeAndSaveVmSystemSerialNumber(spec.getVmInventory().getUuid()));
-        cmd.setGuestOsType(spec.getVmInventory().getGuestOsType());
         if (!NetworkGlobalProperty.CHASSIS_ASSET_TAG.isEmpty()) {
             cmd.setChassisAssetTag(NetworkGlobalProperty.CHASSIS_ASSET_TAG);
         }