Aiming at the typical hydraulic system circuit, the active preventive maintenance based on the fault prediction can make the maintenance guarantee measures more pertinence and get good maintenance effect. From the perspective of this kind of situation and maintenance, maintenance strategy established based on actual demand traction and residual life prediction,is widely used in industry, national defense, aviation and other fields. It is able to improve equipment safety and integrity and to reduce the cost of maintenance support. The traditional preventive maintenance decision model was promoted, and the preventive maintenance decision model was established. Then the online prediction model of residual life based on degenerate data was established, and the residual life distribution was realized based on degradation data. The accelerated degradation test of vertical oil cylinder was designed and its performance degradation data were obtained. The preventive maintenance scheme of the vertical loop was established through the preventive maintenance decision model.