diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index 9ff3ec833..9ea2542ee 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -3944,12 +3944,13 @@ wxString GUI_App::transition_tridid(int trid_id)
     wxString maping_dict[] = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };
 
     if (trid_id >= 128 * 4) {
-        int id_index = 4 + trid_id % 128;
+        trid_id -= 128 * 4;
+        int id_index = trid_id / 4;
         return wxString::Format("%s", maping_dict[id_index]);
     }
     else {
         int id_index = ceil(trid_id / 4);
-        int id_suffix = id_suffix = (trid_id + 1) % 4 == 0 ? 4 : (trid_id + 1) % 4;
+        int id_suffix = trid_id % 4 + 1;
         return wxString::Format("%s%d", maping_dict[id_index], id_suffix);
     }
 }