diff --git a/src/nft.ts b/src/nft.ts
index ef1a0fac..3d0429f3 100644
--- a/src/nft.ts
+++ b/src/nft.ts
@@ -27,6 +27,8 @@ import {
   UploadAssetFromDataUrlParams,
   SearchOption,
   SearchReponse,
+  AinftTokenSearch,
+  AinftCollectionSearch,
 } from './types';
 import Ainft721 from './ainft721';
 import stringify from 'fast-json-stable-stringify';
@@ -269,7 +271,7 @@ export default class Nft extends FactoryBase {
    * @returns
    * @param {NftSearchParams & SearchOption} searchParams
    */
-  searchCollections(searchParams: NftSearchParams & SearchOption): Promise<SearchReponse> {
+  searchCollections(searchParams: NftSearchParams & SearchOption): Promise<SearchReponse<AinftCollectionSearch>> {
     let query: Record<string, any> = {};
     if (searchParams) {
       const { userAddress, nftId, name, symbol, limit, offset } = searchParams;
@@ -283,7 +285,7 @@ export default class Nft extends FactoryBase {
    * Search nft assets on the ain blockchain.
    * @param {NftSearchParams & SearchOption} searchParams
    */
-  searchAssets(searchParams: NftSearchParams & SearchOption): Promise<SearchReponse> {
+  searchAssets(searchParams: NftSearchParams & SearchOption): Promise<SearchReponse<AinftTokenSearch>> {
     let query: Record<string, any> = {};
     if (searchParams) {
       const { userAddress, nftId, name, symbol, limit, offset, tokenId } = searchParams;
diff --git a/src/types.ts b/src/types.ts
index 14292ec0..85448689 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -880,8 +880,8 @@ export interface AinftTokenSearch {
   collectionInfo: AinftCollectionSearch;
 }
 
-export interface SearchReponse {
-  list: Array<AinftCollectionSearch | AinftTokenSearch>,
+export interface SearchReponse<T extends AinftCollectionSearch | AinftTokenSearch> {
+  list: Array<T>,
   isFinal: boolean;
   nextOffset: string;
 }
\ No newline at end of file