Abstract: In order to extensively understand the motion law of main and floating screen frame of vibrating flip-flow screen, mechanical model and vibration differential equation of the vibrating flip-flow screen are established considering the effect of damping. The formulas of amplitude and phase of active and floating screen frame of vibrating flip-flow screen are derived using complex number method and the method of determining phase through quadrant is also proposed. In addition, the amplitude-frequency characteristic curve and phase-frequency characteristic curve of active and floating screen frame of vibrating flip-flow screen are acquired and the factors that influence the movement of active and floating screen frame are analyzed. Eventually, a proposal is presented that changing the mass of floating screen and adjusting shear spring stiffness accordingly can adjust the amplitude ratio of active and floating screen frame under the condition that the working frequency and relative amplitude are basically unchanged. All of these research results will improve the theory support of the design of vibrating flip-flow screen.