diff --git a/internal/core/src/common/FieldData.cpp b/internal/core/src/common/FieldData.cpp
index af089fa4696e3..69015dd2743c0 100644
--- a/internal/core/src/common/FieldData.cpp
+++ b/internal/core/src/common/FieldData.cpp
@@ -100,7 +100,7 @@ FieldDataImpl<Type, is_type_entire_row>::FillFieldData(
     if (element_count == 0) {
         return;
     }
-    null_count = array->null_count();
+    null_count_ = array->null_count();
     switch (data_type_) {
         case DataType::BOOL: {
             AssertInfo(array->type()->id() == arrow::Type::type::BOOL,
@@ -195,6 +195,8 @@ FieldDataImpl<Type, is_type_entire_row>::FillFieldData(
             return FillFieldData(values.data(), element_count);
         }
         case DataType::JSON: {
+            // The code here is not referenced.
+            // A subclass named FieldDataJsonImpl is implemented, which overloads this function.
             AssertInfo(array->type()->id() == arrow::Type::type::BINARY,
                        "inconsistent data type");
             auto json_array =
diff --git a/internal/core/src/common/FieldDataInterface.h b/internal/core/src/common/FieldDataInterface.h
index 72aff36da8b82..5703acce16106 100644
--- a/internal/core/src/common/FieldDataInterface.h
+++ b/internal/core/src/common/FieldDataInterface.h
@@ -484,7 +484,7 @@ class FieldDataImpl : public FieldDataBase {
     int64_t
     get_null_count() const override {
         std::shared_lock lck(tell_mutex_);
-        return null_count;
+        return null_count_;
     }
 
     bool
@@ -507,7 +507,7 @@ class FieldDataImpl : public FieldDataBase {
     // number of elements data_ can hold
     int64_t num_rows_;
     mutable std::shared_mutex num_rows_mutex_;
-    int64_t null_count{0};
+    int64_t null_count_{0};
     // number of actual elements in data_
     size_t length_{};
     mutable std::shared_mutex tell_mutex_;
@@ -616,6 +616,7 @@ class FieldDataJsonImpl : public FieldDataImpl<Json, true> {
         if (n == 0) {
             return;
         }
+        null_count_ = array->null_count();
 
         std::lock_guard lck(tell_mutex_);
         if (length_ + n > get_num_rows()) {
@@ -624,8 +625,11 @@ class FieldDataJsonImpl : public FieldDataImpl<Json, true> {
 
         auto i = 0;
         for (const auto& json : *array) {
-            data_[length_ + i] = Json(simdjson::padded_string(json.value()));
-            i++;
+            if (!json.has_value()) {
+                i++;
+                continue;
+            }
+            data_[length_ + i++] = Json(simdjson::padded_string(json.value()));
         }
         if (IsNullable()) {
             auto valid_data = array->null_bitmap_data();
diff --git a/internal/core/src/storage/Event.cpp b/internal/core/src/storage/Event.cpp
index b76657de3fd12..b35c92c22c155 100644
--- a/internal/core/src/storage/Event.cpp
+++ b/internal/core/src/storage/Event.cpp
@@ -273,10 +273,12 @@ BaseEventData::Serialize() {
                 auto string_view =
                     static_cast<const Json*>(field_data->RawValue(offset))
                         ->data();
+                auto size =
+                    field_data->is_valid(offset) ? string_view.size() : -1;
                 payload_writer->add_one_binary_payload(
                     reinterpret_cast<const uint8_t*>(
                         std::string(string_view).c_str()),
-                    string_view.size());
+                    size);
             }
             break;
         }
diff --git a/internal/core/unittest/test_data_codec.cpp b/internal/core/unittest/test_data_codec.cpp
index 7831454c6a03d..1e836eeb3aa93 100644
--- a/internal/core/unittest/test_data_codec.cpp
+++ b/internal/core/unittest/test_data_codec.cpp
@@ -765,3 +765,32 @@ TEST(storage, InsertDataStringArrayNullable) {
     ASSERT_EQ(*new_payload->ValidData(), *valid_data);
     delete[] valid_data;
 }
+
+TEST(storage, InsertDataJsonNullable) {
+    FixedVector<Json> data = {Json(),
+                              Json(simdjson::padded_string(std::string("A")))};
+    auto field_data =
+        milvus::storage::CreateFieldData(storage::DataType::JSON, true);
+    uint8_t* valid_data = new uint8_t[1]{0x00};
+    field_data->FillFieldData(data.data(), valid_data, data.size());
+
+    storage::InsertData insert_data(field_data);
+    storage::FieldDataMeta field_data_meta{100, 101, 102, 103};
+    insert_data.SetFieldDataMeta(field_data_meta);
+    insert_data.SetTimestamps(0, 100);
+
+    auto serialized_bytes = insert_data.Serialize(storage::StorageType::Remote);
+    std::shared_ptr<uint8_t[]> serialized_data_ptr(serialized_bytes.data(),
+                                                   [&](uint8_t*) {});
+    auto new_insert_data = storage::DeserializeFileData(
+        serialized_data_ptr, serialized_bytes.size());
+    ASSERT_EQ(new_insert_data->GetCodecType(), storage::InsertDataType);
+    ASSERT_EQ(new_insert_data->GetTimeRage(),
+              std::make_pair(Timestamp(0), Timestamp(100)));
+    auto new_payload = new_insert_data->GetFieldData();
+    ASSERT_EQ(new_payload->get_data_type(), storage::DataType::JSON);
+    ASSERT_EQ(new_payload->get_num_rows(), data.size());
+    ASSERT_EQ(new_payload->get_null_count(), 2);
+    ASSERT_EQ(*new_payload->ValidData(), *valid_data);
+    delete[] valid_data;
+}