The piezo-actuated stage is composed of a piezoelectric actuator (PEA) and a positioning mechanism (PM). Due to the existence of hysteretic nonlinearity in the PEA and the friction behavior in the PM, the accurate position control of the piezo-actuated stage is a challenging task. This paper discusses the continuous-time adaptive control for the piezo-actuated stage, where the hysteresis is described by Prandtl-Ishlinskii model. The proposed control law ensures the zero output tracking of the controlled stage. Experimental results show the effectiveness of the proposed method.