Abstract: The dynamics model of giant magnetostrictive actuator (GMA) used in turning system was established and the influence of temperature and pre-stress on output was discussed. The displacements of ideal or hysteresis GMA model appear "roll over" phenomenon under pre-stress. In small incentive magnetic field, the output displacement decreases with increasing the pre-stress, but when incentive is big enough, the trend is opposite. Temperature affects little on the output displacement in small incentive magnetic field, while the output displacement is obvious decrease with the rise of temperature in a bigger incentive magnetic. The results provide theoretical basis for how to deal with the influences of pre-stress, temperature, GMM hysteresis.