The invention relates to a lifting device of a transferring machine head for installing a fully-mechanized working surface. The lifting device comprises two hydraulic oil cylinders, two brackets, a valve set and a cross beam. The brackets and the hydraulic oil cylinders are used in a matching manner and support the cross beam at the upper part. The valve set controls the synchronous motion of the hydraulic oil cylinders so as to keep the cross beam horizontal. By utilizing the lifting device in the invention, the transferring machine head can be stably lifted to the installing position for positioning, so as to ensure safe and high-speed installing work.