diff --git a/src/mito2/src/worker/handle_write.rs b/src/mito2/src/worker/handle_write.rs
index 9b7693710b32..ca9a1b31a391 100644
--- a/src/mito2/src/worker/handle_write.rs
+++ b/src/mito2/src/worker/handle_write.rs
@@ -239,7 +239,7 @@ fn check_op_type(append_mode: bool, request: &WriteRequest) -> Result<()> {
             request.op_type == OpType::Put,
             InvalidRequestSnafu {
                 region_id: request.region_id,
-                reason: "Only put is allowed under append mode",
+                reason: "DELETE is not allowed under append mode",
             }
         );
     }
diff --git a/src/store-api/src/mito_engine_options.rs b/src/store-api/src/mito_engine_options.rs
index cfb26d30892b..4ae4bcd0d362 100644
--- a/src/store-api/src/mito_engine_options.rs
+++ b/src/store-api/src/mito_engine_options.rs
@@ -33,6 +33,7 @@ pub fn is_mito_engine_option_key(key: &str) -> bool {
         "memtable.partition_tree.index_max_keys_per_shard",
         "memtable.partition_tree.data_freeze_threshold",
         "memtable.partition_tree.fork_dictionary_bytes",
+        "append_mode",
     ]
     .contains(&key)
 }
@@ -70,6 +71,7 @@ mod tests {
         assert!(is_mito_engine_option_key(
             "memtable.partition_tree.fork_dictionary_bytes"
         ));
+        assert!(is_mito_engine_option_key("append_mode"));
         assert!(!is_mito_engine_option_key("foo"));
     }
 }
diff --git a/tests/cases/standalone/common/insert/append_mode.result b/tests/cases/standalone/common/insert/append_mode.result
new file mode 100644
index 000000000000..4fe1166ae6e2
--- /dev/null
+++ b/tests/cases/standalone/common/insert/append_mode.result
@@ -0,0 +1,73 @@
+create table if not exists append_mode_on(
+    host string,
+    ts timestamp,
+    cpu double,
+    TIME INDEX (ts),
+    PRIMARY KEY(host)
+)
+engine=mito
+with('append_mode'='true');
+
+Affected Rows: 0
+
+INSERT INTO append_mode_on VALUES ('host1',0, 0), ('host2', 1, 1,);
+
+Affected Rows: 2
+
+INSERT INTO append_mode_on VALUES ('host1',0, 0), ('host2', 1, 1,);
+
+Affected Rows: 2
+
+SELECT * from append_mode_on ORDER BY host, ts;
+
++-------+-------------------------+-----+
+| host  | ts                      | cpu |
++-------+-------------------------+-----+
+| host1 | 1970-01-01T00:00:00     | 0.0 |
+| host1 | 1970-01-01T00:00:00     | 0.0 |
+| host2 | 1970-01-01T00:00:00.001 | 1.0 |
+| host2 | 1970-01-01T00:00:00.001 | 1.0 |
++-------+-------------------------+-----+
+
+-- SQLNESS REPLACE (region\s\d+\(\d+\,\s\d+\)) region
+DELETE FROM append_mode_on WHERE host = 'host1';
+
+Error: 1004(InvalidArguments), Invalid request to region, reason: DELETE is not allowed under append mode
+
+create table if not exists append_mode_off(
+    host string,
+    ts timestamp,
+    cpu double,
+    TIME INDEX (ts),
+    PRIMARY KEY(host)
+)
+engine=mito
+with('append_mode'='false');
+
+Affected Rows: 0
+
+INSERT INTO append_mode_off VALUES ('host1',0, 0), ('host2', 1, 1,);
+
+Affected Rows: 2
+
+INSERT INTO append_mode_off VALUES ('host1',0, 10), ('host2', 1, 11,);
+
+Affected Rows: 2
+
+SELECT * from append_mode_off ORDER BY host, ts;
+
++-------+-------------------------+------+
+| host  | ts                      | cpu  |
++-------+-------------------------+------+
+| host1 | 1970-01-01T00:00:00     | 10.0 |
+| host2 | 1970-01-01T00:00:00.001 | 11.0 |
++-------+-------------------------+------+
+
+DROP TABLE append_mode_on;
+
+Affected Rows: 0
+
+DROP TABLE append_mode_off;
+
+Affected Rows: 0
+
diff --git a/tests/cases/standalone/common/insert/append_mode.sql b/tests/cases/standalone/common/insert/append_mode.sql
new file mode 100644
index 000000000000..a27a66f4e013
--- /dev/null
+++ b/tests/cases/standalone/common/insert/append_mode.sql
@@ -0,0 +1,38 @@
+create table if not exists append_mode_on(
+    host string,
+    ts timestamp,
+    cpu double,
+    TIME INDEX (ts),
+    PRIMARY KEY(host)
+)
+engine=mito
+with('append_mode'='true');
+
+INSERT INTO append_mode_on VALUES ('host1',0, 0), ('host2', 1, 1,);
+
+INSERT INTO append_mode_on VALUES ('host1',0, 0), ('host2', 1, 1,);
+
+SELECT * from append_mode_on ORDER BY host, ts;
+
+-- SQLNESS REPLACE (region\s\d+\(\d+\,\s\d+\)) region
+DELETE FROM append_mode_on WHERE host = 'host1';
+
+create table if not exists append_mode_off(
+    host string,
+    ts timestamp,
+    cpu double,
+    TIME INDEX (ts),
+    PRIMARY KEY(host)
+)
+engine=mito
+with('append_mode'='false');
+
+INSERT INTO append_mode_off VALUES ('host1',0, 0), ('host2', 1, 1,);
+
+INSERT INTO append_mode_off VALUES ('host1',0, 10), ('host2', 1, 11,);
+
+SELECT * from append_mode_off ORDER BY host, ts;
+
+DROP TABLE append_mode_on;
+
+DROP TABLE append_mode_off;