diff --git a/be/src/vec/exec/scan/scanner_context.cpp b/be/src/vec/exec/scan/scanner_context.cpp
index c0a471327d..45e106039f 100644
--- a/be/src/vec/exec/scan/scanner_context.cpp
+++ b/be/src/vec/exec/scan/scanner_context.cpp
@@ -29,7 +29,13 @@ namespace doris::vectorized {
 
 Status ScannerContext::init() {
     _real_tuple_desc = _input_tuple_desc != nullptr ? _input_tuple_desc : _output_tuple_desc;
-    // 1. Calculate how many blocks need to be preallocated.
+    // 1. Calculate max concurrency
+    // TODO: now the max thread num <= config::doris_scanner_thread_pool_thread_num / 4
+    // should find a more reasonable value.
+    _max_thread_num =
+            std::min(config::doris_scanner_thread_pool_thread_num / 4, (int32_t)_scanners.size());
+
+    // 2. Calculate how many blocks need to be preallocated.
     // The calculation logic is as follows:
     //  1. Assuming that at most M rows can be scanned in one scan(config::doris_scanner_row_num),
     //     then figure out how many blocks are required for one scan(_block_per_scanner).
@@ -41,9 +47,7 @@ Status ScannerContext::init() {
     int real_block_size = limit == -1 ? _state->batch_size()
                                       : std::min(static_cast<int64_t>(_state->batch_size()), limit);
     _block_per_scanner = (doris_scanner_row_num + (real_block_size - 1)) / real_block_size;
-    auto pre_alloc_block_count =
-            std::min((int32_t)_scanners.size(), config::doris_scanner_thread_pool_thread_num) *
-            _block_per_scanner;
+    auto pre_alloc_block_count = _max_thread_num * _block_per_scanner;
 
     // The free blocks is used for final output block of scanners.
     // So use _output_tuple_desc;
@@ -52,15 +56,6 @@ Status ScannerContext::init() {
         _free_blocks.emplace_back(block);
     }
 
-    // 2. Calculate max concurrency
-    _max_thread_num = config::doris_scanner_thread_pool_thread_num;
-    if (config::doris_scanner_row_num > _state->batch_size()) {
-        _max_thread_num /= config::doris_scanner_row_num / _state->batch_size();
-        if (_max_thread_num <= 0) {
-            _max_thread_num = 1;
-        }
-    }
-
 #ifndef BE_TEST
     // 3. get thread token
     thread_token = _state->get_query_fragments_ctx()->get_token();
@@ -72,7 +67,7 @@ Status ScannerContext::init() {
 
     _num_unfinished_scanners = _scanners.size();
 
-    COUNTER_SET(_parent->_pre_alloc_free_blocks_num, (int64_t)_free_blocks.size());
+    COUNTER_SET(_parent->_pre_alloc_free_blocks_num, (int64_t)pre_alloc_block_count);
     COUNTER_SET(_parent->_max_scanner_thread_num, (int64_t)_max_thread_num);
 
     return Status::OK();
@@ -223,6 +218,11 @@ void ScannerContext::push_back_scanner_and_reschedule(VScanner* scanner) {
     if (scanner->need_to_close() && scanner->set_counted_down() &&
         (--_num_unfinished_scanners) == 0) {
         _is_finished = true;
+        // ATTN: this 2 counters will be set at close() again, which is the final values.
+        // But we set them here because the counter set at close() can not send to FE's profile.
+        // So we set them here, and the counter value may be little less than final values.
+        COUNTER_SET(_parent->_scanner_sched_counter, _num_scanner_scheduling);
+        COUNTER_SET(_parent->_scanner_ctx_sched_counter, _num_ctx_scheduling);
         _blocks_queue_added_cv.notify_one();
     }
     _ctx_finish_cv.notify_one();