The invention relates to an underwater load rejection device and underwater equipment. The underwater load rejection device comprises a drive mechanism, a first connecting piece and a second connecting piece fixedly connected with a load, wherein the drive device is connected with the first connecting piece and drives the first connecting piece to rotate; when the first connecting piece rotates toa first position, the first connecting piece and the second connecting piece are connected in a clamping way; and when the first connecting piece rotates to a second position, the second connecting piece and the first connecting piece are separated. According to the underwater load rejection device and the underwater equipment provided by the invention, a heavy load can be driven by small drive,heavy weight is converted into a small friction force between the first connecting piece and the second connecting piece, and a motor only needs to overcome a friction torque so as to achieve the aimof load rejection. The magnitude of the friction force is well-leveraged through reducing the friction coefficients of two contact surfaces, so that energy conservation and reliability are realized.