The utility model discloses a way awl warehouse system automatic switch formula rear compartment door mechanism, including the rear compartment door to and the hydraulic power system who links to each other with the rear compartment door. Hydraulic power system includes: the pneumatic cylinder support, the pneumatic cylinder, the operating rod comprises a linkage rod, a spring, threaded step shaft and slide bearing seat, the round pin axle of rear compartment door bottom sets up in the direction spout of gangbar, and it is fixed through gasket and split pin, the fixed longeron of door frame and the round pin axle of rear compartment door link to each other through the hinge, the pneumatic cylinder sets up on the pneumatic cylinder support through the round pin axle, the middle part of gangbar is provided with the linkage pole socket, the output shaft of pneumatic cylinder is through selling the hub connection on the linkage pole socket, be connected with the threaded step shaft through the nut in the gangbar of the output shaft both sides of pneumatic cylinder, threaded step shaft one end is passed through slide bearing and is set up in the slide bearing seat, the spring housing is at the threaded step shaft and by the pre -compaction of slide bearing seat. The utility model discloses a hydraulic system makes control rapidly and stably, improved whole efficiency.