The present invention disclosed an LED light source lampshade with a self-locking and pre-tightening device, which relates to the field of illuminating devices. The LED light source lampshade with a self-locking and pre-tightening device comprises a lampshade and a lamp body, wherein a side wall of the lampshade comprises an outer side wall of the lampshade and a plurality of connecting ribs, wherein a gap is provided between every two adjacent connecting ribs, wherein a limiting slot is provided between each connecting rib and the outer side wall of the lampshade, wherein a length of the connecting rib is greater than the length of the outer side wall of the lampshade, wherein a rotating boss is provided on an outer side surface of each of the plurality of connecting rib, so that the cross section of the side wall of the lampshade is in an approximately “concave” shape; the edge of the upper end surface of the lamp body is surrounded by a plurality of limiting slots, wherein a pre-tightening groove is provided between the adjacent two limiting ribs, wherein a self-locking groove is provided on one end of the pre-tightening groove near the guiding groove, wherein the lamp body is connected with the lampshade, wherein the rotating boss is matched with the pre-tightening groove. The LED light source lampshade with a self-locking and pre-tightening device provided by the present invention has advantages of simple structure, convenient installation and high production efficiency of the lampshade.