Being a symbol of social advance, hydraulic lifting appliance is indispensible to civilization development. Much attention has been paid by lifting industry to the efficiency, security and stability of hydraulic lifting appliance. With ceaseless development of science and technology, more and more new technologies are applied to lifting appliance design. At the same time, the once exist hydraulic oil leakage phenomenon is overcame gradually by the perfection of hydraulic transmission technology and improvement of domestic hydraulic elements quality. As a result, wide application of hydraulic transmission technology on lifting appliance is becoming an inevitable trend. Beginning with the analysis on hydraulic system of the current hydraulic appliance, the essay conducts analysis on hydraulic system with the purpose of improving properties of hydraulic system and finally establishing a stable hydraulic system.