Abstract: In order to solve the problems of low efficiency and large energy consumption existing in the photovoltaic system,this paper proposes a dual-axis tracking strategy with alternating residual variable frequency based on the theme of"energy saving and high efficiency". Based on the model of solar trajectory,this strategy takes the dual-axis tracking device as the research object,controlling the directional motor by comparing the algebraic relationship between the allowable deviation angle and the misfit angle. The directional motor is alternately moved while leaving a certain margin by judging the effect of motor motion in each direction. The simulation shows that the control strategy can effectively reduce the frequency of the tracking system. In the summer solstice of 2018,the total moving numbers of the dual axial motor is 63,which is 12.5% lower than that of the fixed-step strategy,and 21.25% lower than that of the traditional variable frequency strategy.