The invention discloses a storehouse cover opening mechanism of buoyancy compensation storehouse body, which solves the problems of the loud noise of opening the door of the sealed storehouse in the water and the recycling of the recovered materials. Two hangers shaped like an inverted T are respectively hung on the storehouse cover (3). A push-pull electromagnet (10) is connected with the bottom of the two hangers shaped like an inverted T. A circular tube (14) is movably sheathed on the upper end of the electromagnet (13). The steps among the bottom of the circular tube (14), the side wall of the electromagnet (13), and the right hanger shaped liked an inverted T(5) are provided with a low limit steel ball(17). The steps among the bottom of the circular tube (14), the side wall of the electromagnet (13), and the left hanger shaped liked an inverted T(7) are provided with the other low limit steel ball. The bottom of the annular limit groove (21), the storehouse cover (3) and the top of the cylindrical cap (15) are provided with upper limit steel balls at intervals (22). The storehouse cover opening mechanism of buoyancy compensation storehouse body has the advantages of being low in noise of opening the storehouse cover in the water and realizable in the recycling of the opening mechanism.