diff --git a/tests/ut/test_search.cc b/tests/ut/test_search.cc
index 33edb70bf..aea7896b3 100644
--- a/tests/ut/test_search.cc
+++ b/tests/ut/test_search.cc
@@ -32,9 +32,9 @@ TEST_CASE("Test Mem Index With Float Vector", "[float metrics]") {
 
     const int64_t nb = 1000, nq = 10;
     const int64_t dim = 128;
-    const int64_t topk = 5;
 
     auto metric = GENERATE(as<std::string>{}, knowhere::metric::L2, knowhere::metric::COSINE);
+    auto topk = GENERATE(as<int64_t>{}, 5, 120);
     auto version = GenTestVersionList();
 
     auto base_gen = [=]() {
@@ -89,7 +89,7 @@ TEST_CASE("Test Mem Index With Float Vector", "[float metrics]") {
         knowhere::Json json = base_gen();
         json[knowhere::indexparam::HNSW_M] = 128;
         json[knowhere::indexparam::EFCONSTRUCTION] = 200;
-        json[knowhere::indexparam::EF] = 64;
+        json[knowhere::indexparam::EF] = 200;
         return json;
     };
 
@@ -270,9 +270,9 @@ TEST_CASE("Test Mem Index With Binary Vector", "[float metrics]") {
 
     const int64_t nb = 1000, nq = 10;
     const int64_t dim = 1024;
-    const int64_t topk = 5;
 
     auto metric = GENERATE(as<std::string>{}, knowhere::metric::HAMMING, knowhere::metric::JACCARD);
+    auto topk = GENERATE(as<int64_t>{}, 5, 120);
     auto version = GenTestVersionList();
     auto base_gen = [=]() {
         knowhere::Json json;
@@ -288,7 +288,7 @@ TEST_CASE("Test Mem Index With Binary Vector", "[float metrics]") {
     auto ivfflat_gen = [base_gen]() {
         knowhere::Json json = base_gen();
         json[knowhere::indexparam::NLIST] = 16;
-        json[knowhere::indexparam::NPROBE] = 8;
+        json[knowhere::indexparam::NPROBE] = 14;
         return json;
     };
 
@@ -296,7 +296,7 @@ TEST_CASE("Test Mem Index With Binary Vector", "[float metrics]") {
         knowhere::Json json = base_gen();
         json[knowhere::indexparam::HNSW_M] = 128;
         json[knowhere::indexparam::EFCONSTRUCTION] = 200;
-        json[knowhere::indexparam::EF] = 64;
+        json[knowhere::indexparam::EF] = 200;
         return json;
     };
 
@@ -377,11 +377,11 @@ TEST_CASE("Test Mem Index With Binary Vector", "[bool metrics]") {
     using Catch::Approx;
 
     const int64_t nb = 1000, nq = 10;
-    const int64_t topk = 5;
 
     auto dim = GENERATE(as<int64_t>{}, 8, 16, 32, 64, 128, 256, 512, 160);
     auto version = GenTestVersionList();
     auto metric = GENERATE(as<std::string>{}, knowhere::metric::SUPERSTRUCTURE, knowhere::metric::SUBSTRUCTURE);
+    auto topk = GENERATE(as<int64_t>{}, 5, 100);
 
     auto base_gen = [=]() {
         knowhere::Json json;
@@ -441,11 +441,17 @@ TEST_CASE("Test Mem Index With Binary Vector", "[bool metrics]") {
         auto code_size = dim / 8;
         for (int64_t i = 0; i < nq; i++) {
             const uint8_t* query_vector = (const uint8_t*)query_ds->GetTensor() + i * code_size;
-            std::vector<int64_t> ids_v(ids + i * topk, ids + (i + 1) * topk);
-            auto ds = GenIdsDataSet(topk, ids_v);
+            // filter out -1 when the result num less than topk
+            int64_t real_topk = 0;
+            for (; real_topk < topk; real_topk++) {
+                if (ids[i * topk + real_topk] < 0)
+                    break;
+            }
+            std::vector<int64_t> ids_v(ids + i * topk, ids + i * topk + real_topk);
+            auto ds = GenIdsDataSet(real_topk, ids_v);
             auto gv_res = idx.GetVectorByIds(*ds);
             REQUIRE(gv_res.has_value());
-            for (int64_t j = 0; j < topk; j++) {
+            for (int64_t j = 0; j < real_topk; j++) {
                 const uint8_t* res_vector = (const uint8_t*)gv_res.value()->GetTensor() + j * code_size;
                 if (metric == knowhere::metric::SUPERSTRUCTURE) {
                     REQUIRE(faiss::is_subset(res_vector, query_vector, code_size));