diff --git a/internal/core/unittest/test_index_wrapper.cpp b/internal/core/unittest/test_index_wrapper.cpp
index 79581bc969..ffef4a8fc2 100644
--- a/internal/core/unittest/test_index_wrapper.cpp
+++ b/internal/core/unittest/test_index_wrapper.cpp
@@ -172,9 +172,9 @@ TEST_P(IndexWrapperTest, BuildAndQuery) {
     search_info.search_params_ = search_conf;
     std::unique_ptr<SearchResult> result;
     if (vec_field_data_type == DataType::VECTOR_FLOAT) {
-        auto dataset = GenDataset(NB, metric_type, false);
+        auto nb_for_nq = NQ + query_offset;
+        auto dataset = GenDataset(nb_for_nq, metric_type, false);
         auto xb_data = dataset.get_col<float>(milvus::FieldId(100));
-        auto xb_dataset = knowhere::GenDataSet(NB, DIM, xb_data.data());
         auto xq_dataset =
             knowhere::GenDataSet(NQ, DIM, xb_data.data() + DIM * query_offset);
         result = vec_index->Query(xq_dataset, search_info, nullptr);
@@ -188,11 +188,12 @@ TEST_P(IndexWrapperTest, BuildAndQuery) {
         xq_dataset->SetIsSparse(true);
         result = vec_index->Query(xq_dataset, search_info, nullptr);
     } else {
-        auto dataset = GenDataset(NB, metric_type, true);
+        auto nb_for_nq = NQ + query_offset;
+        auto dataset = GenDataset(nb_for_nq, metric_type, true);
         auto xb_bin_data = dataset.get_col<uint8_t>(milvus::FieldId(100));
-        auto xb_dataset = knowhere::GenDataSet(NB, DIM, xb_bin_data.data());
+        // offset of binary vector is 8-aligned bit-wise representation.
         auto xq_dataset = knowhere::GenDataSet(
-            NQ, DIM, xb_bin_data.data() + DIM * query_offset);
+            NQ, DIM, xb_bin_data.data() + ((DIM + 7) / 8) * query_offset);
         result = vec_index->Query(xq_dataset, search_info, nullptr);
     }