The piezo-actuated stages are composed of the piezo-electric actuator and the positioning mechanism. The positioning accuracy of the piezo-actuated stage is limited due to hysteretic nonlinearity of the PEA and friction behavior of the positioning mechanism. To compensate this nonlinearity of piezoelectric actuator, a PI feedback control associated with feedforward compensating based on the hysteresis observer is proposed in this paper. Identifying its parameters is very important; so the genetic algorithm is studied to find the optimal parameters. To verify the feasibility of the proposed method, it is implemented on the precision positioning task of the piezo-actuated stage in the real-time control architecture.