diff --git a/__tests__/tree.spec.ts b/__tests__/tree.spec.ts
index 6b78c32..021eda1 100644
--- a/__tests__/tree.spec.ts
+++ b/__tests__/tree.spec.ts
@@ -74,6 +74,18 @@ describe('Tree related methods', () => {
     expect(graph.getChildren(1).map((n) => n.id)).toEqual([3]);
   });
 
+  test('Remove parent', () => {
+    const graph = initTreeGraph();
+    graph.setParent(2, 4);
+    expect(graph.getParent(2)?.id).toEqual(4);
+    graph.setParent(2, null);
+    expect(graph.getParent(2)).toEqual(null);
+
+    graph.setParent(2, 1);
+    expect(graph.getParent(2)?.id).toEqual(1);
+    graph.setParent(2); // use undefined to remove parent
+  });
+
   test('Removing nodes', () => {
     const graph = initTreeGraph();
     graph.removeNode(1);
diff --git a/package.json b/package.json
index ceeb668..420fcc7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@antv/graphlib",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "main": "lib/index.js",
   "module": "esm/index.js",
   "types": "lib/index.d.ts",
@@ -35,14 +35,14 @@
   "devDependencies": {
     "@commitlint/cli": "^11.0.0",
     "@rollup/plugin-commonjs": "^21.1.0",
-    "@rollup/plugin-node-resolve": "^15.2.3",
+    "@rollup/plugin-node-resolve": "^15.3.0",
     "@rollup/plugin-terser": "^0.4.4",
-    "@types/jest": "^29.5.12",
+    "@types/jest": "^29.5.14",
     "@typescript-eslint/eslint-plugin": "^5.62.0",
     "@typescript-eslint/parser": "^5.62.0",
     "cross-env": "^7.0.3",
-    "eslint": "^8.57.0",
-    "eslint-plugin-import": "^2.29.1",
+    "eslint": "^8.57.1",
+    "eslint-plugin-import": "^2.31.0",
     "husky": "^8.0.3",
     "jest": "^29.7.0",
     "limit-size": "^0.1.4",
@@ -50,12 +50,12 @@
     "npm-run-all": "^4.1.5",
     "prettier": "^2.8.8",
     "rimraf": "^3.0.2",
-    "rollup": "^2.79.1",
+    "rollup": "^2.79.2",
     "rollup-plugin-polyfill-node": "^0.8.0",
     "rollup-plugin-typescript2": "^0.35.0",
     "rollup-plugin-visualizer": "^5.12.0",
-    "ts-jest": "^29.1.5",
-    "tslib": "^2.6.3",
+    "ts-jest": "^29.2.5",
+    "tslib": "^2.8.1",
     "typedoc": "^0.25.13",
     "typedoc-plugin-markdown": "^3.17.1",
     "typescript": "^4.9.5"
diff --git a/src/graph.ts b/src/graph.ts
index 9aafa61..78a9dfd 100644
--- a/src/graph.ts
+++ b/src/graph.ts
@@ -1008,22 +1008,25 @@ export class Graph<
   /**
    * Set node parent. If this operation causes a circle, it fails with an error.
    * @param id - ID of the child node.
-   * @param parent - ID of the parent node. If it is undefined, means unset parent for node with id.
+   * @param parent - ID of the parent node. If it is undefined or null, means unset parent for node with id.
    * @param treeKey - Which tree structure the relation is applied to.
    * @group TreeMethods
    */
-  public setParent(id: ID, parent?: ID, treeKey?: string) {
+  public setParent(id: ID, parent?: ID | null, treeKey?: string) {
     this.checkTreeExistence(treeKey);
 
-    const tree = this.treeIndices.get(treeKey)!;
+    const tree = this.treeIndices.get(treeKey);
+
+    if (!tree) return;
+
     const node = this.getNode(id);
     const oldParent = tree.parentMap.get(id);
 
     // Same parent id as old one, skip
     if (oldParent?.id === parent) return;
 
-    // New parent is undefined, unset parent for the node
-    if (parent === undefined) {
+    // New parent is undefined or null, unset parent for the node
+    if (parent === undefined || parent === null) {
       if (oldParent) {
         tree.childrenMap.get(oldParent.id)?.delete(node);
       }