Positioning precision of giant magnetostrictive actuator (GMA) is seriously effected by hysteresis nonlinearity of giant magnetostrictive material (GMM). To solve the problem, based on improved Prandtl-Ishlinskii model and experimental data, the hysteresis model related to the stress of GMA and its hysteresis inverse model were established in the paper. The proportional controller with feedforward compensation using the improved Prandtl-Ishlinskii inverse model of GMA was designed. The measuring and controlling system for GMA were established, and the experiments were carried out. Simulation and experimental results show that the method proposed in the paper can realize precision positioning with high accuracy.