The invention discloses a hydraulic lifting system. The hydraulic lifting system comprises a control device, a transmission device and a hydraulic device. The hydraulic lifting system is characterized in that the control device is connected with the transmission device, the transmission device is connected with the hydraulic device, the tail end of the hydraulic device is connected with a dust collection barrel, the dust collection barrel and the hydraulic device are located inside an ash discharge cylinder, the outer wall of the dust collection barrel is close to the inner wall of the ash discharge barrel, and a dust collection chamber is arranged in the ash discharge barrel. According to the hydraulic lifting system, a truck can be loaded with dry ash smoothly in an unimpeded mode by means of the stable lifting of the hydraulic lifting device, ash emitting and ash leaking are effectively prevented, potential safety hazards are avoided, and the utilization efficiency of equipment is improved.