A control method was presented based on variable frequency speed control for the independent position closedloop and pressure closedloop in order to realize the multi parameter adjustment and control of the fullhydraulic leveler and to improve the working efficiency and control precision of hydraulic system. The online real time stepless change of the hydraulic system flow was realized by using frequency conversion motor instead of ordinary three phase induction motor to drive the fixed volume pump, the constant pressure control of the fullhydraulic leveler was realized by using the proportional relief valve instead of the electromagnetic relief valve, the online pressure of the stepless change could be realized according to different plate thickness, and the accurate control of the hydraulic cylinder position was realized by using a builtin magnetostrictive displacement sensor to realtime feedback displacement of the hydraulic cylinder piston rod. A double loop control model of the position closedloop and pressure closedloop of the fullhydraulic leveler was established, and the correctness of the control method was proved by simulation in AMESim software. Finally the feasibility and practicability of the control method is verified by the eleven roll fullhydraulic leveler in the production. 