diff --git a/src/libslic3r/LayerRegion.cpp b/src/libslic3r/LayerRegion.cpp
index 0c9102dea2..c84786c635 100644
--- a/src/libslic3r/LayerRegion.cpp
+++ b/src/libslic3r/LayerRegion.cpp
@@ -225,7 +225,9 @@ void LayerRegion::process_external_surfaces(const Layer *lower_layer, const Poly
                         break;
                     }
                 // Grown by 3mm.
-                Polygons polys = offset(bridges[i].expolygon, bridge_margin, EXTERNAL_SURFACES_OFFSET_PARAMETERS);
+                //BBS: eliminate too narrow area to avoid generating bridge on top layer when wall loop is 1
+                //Polygons polys = offset(bridges[i].expolygon, bridge_margin, EXTERNAL_SURFACES_OFFSET_PARAMETERS);
+                Polygons polys = offset2({ bridges[i].expolygon }, -scale_(nozzle_diameter * 0.1), bridge_margin, EXTERNAL_SURFACES_OFFSET_PARAMETERS);
                 if (idx_island == -1) {
 				    BOOST_LOG_TRIVIAL(trace) << "Bridge did not fall into the source region!";
                 } else {