diff --git a/src/main/java/run/halo/app/controller/content/api/PostController.java b/src/main/java/run/halo/app/controller/content/api/PostController.java
index e3f647a5f..b615f64ea 100644
--- a/src/main/java/run/halo/app/controller/content/api/PostController.java
+++ b/src/main/java/run/halo/app/controller/content/api/PostController.java
@@ -13,6 +13,7 @@ import run.halo.app.model.dto.BaseCommentDTO;
 import run.halo.app.model.dto.post.BasePostDetailDTO;
 import run.halo.app.model.dto.post.BasePostSimpleDTO;
 import run.halo.app.model.entity.Post;
+import run.halo.app.model.entity.PostComment;
 import run.halo.app.model.enums.CommentStatus;
 import run.halo.app.model.enums.PostStatus;
 import run.halo.app.model.params.PostCommentParam;
@@ -88,9 +89,12 @@ public class PostController {
 
     @GetMapping("{postId:\\d+}/comments/{commentParentId:\\d+}/children")
     public List<BaseCommentDTO> listChildrenBy(@PathVariable("postId") Integer postId,
-                                               @PathVariable("commentParentId") Integer commentParentId,
+                                               @PathVariable("commentParentId") Long commentParentId,
                                                @SortDefault(sort = "createTime", direction = DESC) Sort sort) {
-        return postCommentService.listChildrenBy(postId, commentParentId, CommentStatus.PUBLISHED, sort);
+        // Find all children comments
+        List<PostComment> postComments = postCommentService.listChildrenBy(postId, commentParentId, CommentStatus.PUBLISHED, sort);
+        // Convert to base comment dto
+        return postCommentService.convertTo(postComments);
     }
 
 
diff --git a/src/main/java/run/halo/app/repository/base/BaseCommentRepository.java b/src/main/java/run/halo/app/repository/base/BaseCommentRepository.java
index 6385adc7b..524508f01 100644
--- a/src/main/java/run/halo/app/repository/base/BaseCommentRepository.java
+++ b/src/main/java/run/halo/app/repository/base/BaseCommentRepository.java
@@ -94,6 +94,27 @@ public interface BaseCommentRepository<COMMENT extends BaseComment> extends Base
     @NonNull
     Page<COMMENT> findAllByPostIdAndStatus(Integer postId, CommentStatus status, Pageable pageable);
 
+    /**
+     * Finds comments by post id, comment status and parent id.
+     *
+     * @param postId   post id must not be null
+     * @param status   comment status must not be null
+     * @param parentId comment parent id must not be null
+     * @return a list of comment
+     */
+    @NonNull
+    List<COMMENT> findAllByPostIdAndStatusAndParentId(Integer postId, CommentStatus status, Long parentId);
+
+    /**
+     * Finds all comments by status and parent id collection.
+     *
+     * @param status    comment status must not be null
+     * @param parentIds parent id collection must not be null
+     * @return a list of comment
+     */
+    @NonNull
+    List<COMMENT> findAllByStatusAndParentIdIn(@NonNull CommentStatus status, @NonNull Iterable<Long> parentIds);
+
     /**
      * Finds comments by post id, comment status and parent id.
      *
@@ -106,6 +127,7 @@ public interface BaseCommentRepository<COMMENT extends BaseComment> extends Base
     @NonNull
     Page<COMMENT> findAllByPostIdAndStatusAndParentId(Integer postId, CommentStatus status, Long parentId, Pageable pageable);
 
+
     @Query("select new run.halo.app.model.projection.CommentChildrenCountProjection(count(comment.id), comment.parentId) " +
             "from BaseComment comment " +
             "where comment.parentId in ?1 " +
diff --git a/src/main/java/run/halo/app/service/base/BaseCommentService.java b/src/main/java/run/halo/app/service/base/BaseCommentService.java
index d31a1843d..87c2a0043 100644
--- a/src/main/java/run/halo/app/service/base/BaseCommentService.java
+++ b/src/main/java/run/halo/app/service/base/BaseCommentService.java
@@ -213,5 +213,5 @@ public interface BaseCommentService<COMMENT extends BaseComment> extends CrudSer
      * @return a list of children comment
      */
     @NonNull
-    List<BaseCommentDTO> listChildrenBy(@NonNull Integer targetId, @NonNull Integer commentParentId, @NonNull CommentStatus status, @NonNull Sort sort);
+    List<COMMENT> listChildrenBy(@NonNull Integer targetId, @NonNull Long commentParentId, @NonNull CommentStatus status, @NonNull Sort sort);
 }
diff --git a/src/main/java/run/halo/app/service/impl/BaseCommentServiceImpl.java b/src/main/java/run/halo/app/service/impl/BaseCommentServiceImpl.java
index 1b28d73ba..bbcac107b 100644
--- a/src/main/java/run/halo/app/service/impl/BaseCommentServiceImpl.java
+++ b/src/main/java/run/halo/app/service/impl/BaseCommentServiceImpl.java
@@ -445,12 +445,55 @@ public abstract class BaseCommentServiceImpl<COMMENT extends BaseComment> extend
     }
 
     @Override
-    public List<BaseCommentDTO> listChildrenBy(Integer targetId, Integer commentParentId, CommentStatus status, Sort sort) {
+    public List<COMMENT> listChildrenBy(Integer targetId, Long commentParentId, CommentStatus status, Sort sort) {
         Assert.notNull(targetId, "Target id must not be null");
         Assert.notNull(commentParentId, "Comment parent id must not be null");
         Assert.notNull(sort, "Sort info must not be null");
 
-        return null;
+        // Get comments recursively
+
+        // Get direct children
+        List<COMMENT> directChildren = baseCommentRepository.findAllByPostIdAndStatusAndParentId(targetId, status, commentParentId);
+
+        // Create result container
+        Set<COMMENT> children = new HashSet<>();
+
+        // Get children comments
+        getChildrenRecursively(directChildren, status, children);
+
+        // Sort children
+        List<COMMENT> childrenList = new ArrayList<>(children);
+        childrenList.sort(Comparator.comparing(BaseComment::getId));
+
+        return childrenList;
+    }
+
+    /**
+     * Get children comments recursively.
+     *
+     * @param topComments top comment list
+     * @param status      comment status must not be null
+     * @param children    children result must not be null
+     */
+    private void getChildrenRecursively(@Nullable List<COMMENT> topComments, @NonNull CommentStatus status, @NonNull Set<COMMENT> children) {
+        Assert.notNull(status, "Comment status must not be null");
+        Assert.notNull(children, "Children comment set must not be null");
+
+        if (CollectionUtils.isEmpty(topComments)) {
+            return;
+        }
+
+        // Convert comment id set
+        Set<Long> commentIds = ServiceUtils.fetchProperty(topComments, COMMENT::getId);
+
+        // Get direct children
+        List<COMMENT> directChildren = baseCommentRepository.findAllByStatusAndParentIdIn(status, commentIds);
+
+        // Recursively invoke
+        getChildrenRecursively(directChildren, status, children);
+
+        // Add direct children to children result
+        children.addAll(topComments);
     }
 
     /**
diff --git a/src/main/java/run/halo/app/utils/ServiceUtils.java b/src/main/java/run/halo/app/utils/ServiceUtils.java
index 7cf80a0f6..a03bec409 100644
--- a/src/main/java/run/halo/app/utils/ServiceUtils.java
+++ b/src/main/java/run/halo/app/utils/ServiceUtils.java
@@ -31,6 +31,7 @@ public class ServiceUtils {
      * @param <T>             data type
      * @return a set of id
      */
+    @NonNull
     public static <ID, T> Set<ID> fetchProperty(final Collection<T> datas, Function<T, ID> mappingFunction) {
         return CollectionUtils.isEmpty(datas) ?
                 Collections.emptySet() :
@@ -47,6 +48,7 @@ public class ServiceUtils {
      * @param <D>             data type
      * @return a map which key is in ids and value containing in list
      */
+    @NonNull
     public static <ID, D> Map<ID, List<D>> convertToListMap(Collection<ID> ids, Collection<D> list, Function<D, ID> mappingFunction) {
         Assert.notNull(mappingFunction, "mapping function must not be null");
 
@@ -72,6 +74,7 @@ public class ServiceUtils {
      * @param <D>             data type
      * @return a map which key from list data and value is data
      */
+    @NonNull
     public static <ID, D> Map<ID, D> convertToMap(Collection<D> list, Function<D, ID> mappingFunction) {
         Assert.notNull(mappingFunction, "mapping function must not be null");
 
@@ -97,6 +100,7 @@ public class ServiceUtils {
      * @param <V>           value type
      * @return a map which key from list data and value is data
      */
+    @NonNull
     public static <ID, D, V> Map<ID, V> convertToMap(Collection<D> list, Function<D, ID> keyFunction, Function<D, V> valueFunction) {
         Assert.notNull(keyFunction, "mapping function must not be null");