The utility model discloses a device for preventing R bayonet lock drops, the device includes a cylinder section of thick bamboo (1) of back cover, the symmetry is provided with a threaded holes and second screw hole that runs through a cylinder section of thick bamboo (1) wall on being close to a cylinder section of thick bamboo (1) circumference surface of a cylinder section of thick bamboo (1) port, still include first bolt (2) and second bolt (3) with the corresponding cooperation spiro union of a threaded holes and second screw hole, wherein, first bolt (2) and second bolt (3) are followed one end that a cylinder section of thick bamboo (1) outer wall rotation passed a corresponding threaded holes and second screw hole and passed a threaded holes and second screw hole respectively and are fixed with the first semicircle ring (5) that has the screw thread respectively and encircle (6) with the second semicircle, the device can guarantee that the R bayonet lock does not experience and expose to wind and rain, and then avoids that the R bayonet lock gets rusty, the phenomenon of rupture takes place to avoid the drop emergence of phenomenon of bolt and nut, ensure that bolt and nut cooperate the use for a long time, improve the safety in utilization ability.