A foldable rail-mounted crane stop device includes an actuating device, a slidably fixing device and a braking device. The actuating device is mounted on a crane rail for bearing the pressure of a crane wheel and thereby actuating the braking device, the slidably fixing device is mounted at an end of the crane rail, and the braking device is connected with the slidably fixing device for braking the crane wheel. The device provided by the present invention is used for crane braking at the end of a rail.