The invention relates to the technical field of vehicle automatic transmission development, in particular to a brake for an automatic transmission. The brake for the automatic transmission comprises a box body, pistons, a hinge pin, a sealing ring, friction plates, steel sheets, disk springs, pressing plates and bolts. The steel sheets are connected with the box body through the hinge pin. The friction plates are connected with a rotating shaft of a component to be braked through internal splines. The disk springs are arranged between the steel sheets, the steel sheets are connected with the box body through the hinge pin to transmit torque, and therefore when the torque is transmitted, resetting of the pistons is achieved through the disk springs. In addition, the purpose that the intervals of the frication plates are equal is guaranteed through the disk springs, so that the idler loss of the friction plates is effectively reduced, the efficiency of the automatic transmission is improved, and the service life of the brake is prolonged. When the brake for the automatic transmission is used, separation and reunion of the brake are achieved through oil blast and oil discharging of an oil cylinder, and therefore manipulation of the automatic transmission is achieved.