diff --git a/.changelog/3374.txt b/.changelog/3374.txt
new file mode 100644
index 0000000000..74b2900673
--- /dev/null
+++ b/.changelog/3374.txt
@@ -0,0 +1,3 @@
+```release-note:enhancement
+resource/tencentcloud_mqtt_instance: support `automatic_activation` field edit
+```
\ No newline at end of file
diff --git a/tencentcloud/services/mqtt/resource_tc_mqtt_instance.go b/tencentcloud/services/mqtt/resource_tc_mqtt_instance.go
index 2ed1220c3b..ce872e528e 100644
--- a/tencentcloud/services/mqtt/resource_tc_mqtt_instance.go
+++ b/tencentcloud/services/mqtt/resource_tc_mqtt_instance.go
@@ -25,7 +25,7 @@ func ResourceTencentCloudMqttInstance() *schema.Resource {
 			"instance_type": {
 				Type:        schema.TypeString,
 				Required:    true,
-				Description: "Instance type,\nBASIC for Basic Edition\nPRO for Professional Edition.",
+				Description: "Instance type. PRO for Professional Edition; PLATINUM for Platinum Edition.",
 			},
 
 			"name": {
@@ -100,8 +100,9 @@ func ResourceTencentCloudMqttInstance() *schema.Resource {
 
 			"automatic_activation": {
 				Type:        schema.TypeBool,
+				Optional:    true,
 				Computed:    true,
-				Description: "Is the automatic registration certificate automatically activated.",
+				Description: "Is the automatic registration certificate automatically activated. Default is false.",
 			},
 
 			"force_delete": {
@@ -225,6 +226,30 @@ func ResourceTencentCloudMqttInstanceCreate(d *schema.ResourceData, meta interfa
 		return reqErr
 	}
 
+	// open automatic_activation
+	if v, ok := d.GetOkExists("automatic_activation"); ok {
+		if v.(bool) {
+			modifyRequest := mqttv20240516.NewModifyInstanceRequest()
+			modifyRequest.InstanceId = &instanceId
+			modifyRequest.AutomaticActivation = helper.Bool(v.(bool))
+			reqErr := resource.Retry(tccommon.WriteRetryTimeout, func() *resource.RetryError {
+				result, e := meta.(tccommon.ProviderMeta).GetAPIV3Conn().UseMqttV20240516Client().ModifyInstanceWithContext(ctx, modifyRequest)
+				if e != nil {
+					return tccommon.RetryError(e)
+				} else {
+					log.Printf("[DEBUG]%s api[%s] success, request body [%s], response body [%s]\n", logId, modifyRequest.GetAction(), modifyRequest.ToJsonString(), result.ToJsonString())
+				}
+
+				return nil
+			})
+
+			if reqErr != nil {
+				log.Printf("[CRITAL]%s update mqtt failed, reason:%+v", logId, reqErr)
+				return reqErr
+			}
+		}
+	}
+
 	if tags := helper.GetTags(d, "tags"); len(tags) > 0 {
 		tagService := svctag.NewTagService(meta.(tccommon.ProviderMeta).GetAPIV3Conn())
 		region := meta.(tccommon.ProviderMeta).GetAPIV3Conn().Region
@@ -354,6 +379,10 @@ func ResourceTencentCloudMqttInstanceUpdate(d *schema.ResourceData, meta interfa
 			request.SkuCode = helper.String(v.(string))
 		}
 
+		if v, ok := d.GetOkExists("automatic_activation"); ok {
+			request.AutomaticActivation = helper.Bool(v.(bool))
+		}
+
 		reqErr := resource.Retry(tccommon.WriteRetryTimeout, func() *resource.RetryError {
 			result, e := meta.(tccommon.ProviderMeta).GetAPIV3Conn().UseMqttV20240516Client().ModifyInstanceWithContext(ctx, request)
 			if e != nil {
diff --git a/tencentcloud/services/mqtt/resource_tc_mqtt_instance.md b/tencentcloud/services/mqtt/resource_tc_mqtt_instance.md
index 55b430942d..ea9010caa5 100644
--- a/tencentcloud/services/mqtt/resource_tc_mqtt_instance.md
+++ b/tencentcloud/services/mqtt/resource_tc_mqtt_instance.md
@@ -26,9 +26,9 @@ resource "tencentcloud_subnet" "subnet" {
 
 // create mqtt instance
 resource "tencentcloud_mqtt_instance" "example" {
-  instance_type = "BASIC"
+  instance_type = "PRO"
   name          = "tf-example"
-  sku_code      = "basic_2k"
+  sku_code      = "pro_6k_1"
   remark        = "remarks."
   vpc_list {
     vpc_id    = tencentcloud_vpc.vpc.id
@@ -67,16 +67,17 @@ resource "tencentcloud_subnet" "subnet" {
 resource "tencentcloud_mqtt_instance" "example" {
   instance_type = "PRO"
   name          = "tf-example"
-  sku_code      = "pro_6k_1"
+  sku_code      = "pro_10k_2"
   remark        = "remarks."
   vpc_list {
     vpc_id    = tencentcloud_vpc.vpc.id
     subnet_id = tencentcloud_subnet.subnet.id
   }
-  pay_mode     = 1
-  time_span    = 1
-  renew_flag   = 1
-  force_delete = false
+  pay_mode             = 1
+  time_span            = 1
+  renew_flag           = 1
+  force_delete         = false
+  automatic_activation = true
   tags = {
     createBy = "Terraform"
   }
diff --git a/website/docs/r/mqtt_instance.html.markdown b/website/docs/r/mqtt_instance.html.markdown
index 5a3fe925bb..1123ea5571 100644
--- a/website/docs/r/mqtt_instance.html.markdown
+++ b/website/docs/r/mqtt_instance.html.markdown
@@ -37,9 +37,9 @@ resource "tencentcloud_subnet" "subnet" {
 
 // create mqtt instance
 resource "tencentcloud_mqtt_instance" "example" {
-  instance_type = "BASIC"
+  instance_type = "PRO"
   name          = "tf-example"
-  sku_code      = "basic_2k"
+  sku_code      = "pro_6k_1"
   remark        = "remarks."
   vpc_list {
     vpc_id    = tencentcloud_vpc.vpc.id
@@ -78,16 +78,17 @@ resource "tencentcloud_subnet" "subnet" {
 resource "tencentcloud_mqtt_instance" "example" {
   instance_type = "PRO"
   name          = "tf-example"
-  sku_code      = "pro_6k_1"
+  sku_code      = "pro_10k_2"
   remark        = "remarks."
   vpc_list {
     vpc_id    = tencentcloud_vpc.vpc.id
     subnet_id = tencentcloud_subnet.subnet.id
   }
-  pay_mode     = 1
-  time_span    = 1
-  renew_flag   = 1
-  force_delete = false
+  pay_mode             = 1
+  time_span            = 1
+  renew_flag           = 1
+  force_delete         = false
+  automatic_activation = true
   tags = {
     createBy = "Terraform"
   }
@@ -98,11 +99,10 @@ resource "tencentcloud_mqtt_instance" "example" {
 
 The following arguments are supported:
 
-* `instance_type` - (Required, String) Instance type,
-BASIC for Basic Edition
-PRO for Professional Edition.
+* `instance_type` - (Required, String) Instance type. PRO for Professional Edition; PLATINUM for Platinum Edition.
 * `name` - (Required, String) Instance name.
 * `sku_code` - (Required, String) Product SKU, available SKUs can be queried via the DescribeProductSKUList API.
+* `automatic_activation` - (Optional, Bool) Is the automatic registration certificate automatically activated. Default is false.
 * `force_delete` - (Optional, Bool) Indicate whether to force delete the instance. Default is `false`. If set true, the instance will be permanently deleted instead of being moved into the recycle bin. Note: only works for `PREPAID` instance.
 * `pay_mode` - (Optional, Int) Payment mode (0: Postpaid; 1: Prepaid).
 * `remark` - (Optional, String) Remarks.
@@ -121,7 +121,6 @@ The `vpc_list` object supports the following:
 In addition to all arguments above, the following attributes are exported:
 
 * `id` - ID of the resource.
-* `automatic_activation` - Is the automatic registration certificate automatically activated.
 * `device_certificate_provision_type` - Client certificate registration method: JITP: Automatic registration; API: Manually register through the API.