The invention provides a steel rail locking device. The steel rail locking device comprises a driver, a transmission assembly and a clamp, wherein the clamp comprises a locking part for pressing the rail bottom of a steel rail; one end of the transmission assembly is connected with the clamp, and the other end of the transmission assembly is connected with the driver; and the driver is used for driving the transmission assembly to move so as to enable the clamp to move towards the steel rail and press the rail bottom. The steel rail locking device provided by the invention can achieve automatic locking and a large amount of manual operation is not required, so that the steel rail fixing labor intensity is reduced and the working efficiency is improved.