Abstract: The finite element model of flip-flop screen was established by finite element software. The first eight-order vibration shape was obtained by modal analysis. The suitable working frequency of the screen machine was found. The distribution law of each part of the screen machine strain was obtained by the stress analysis. The principal stress and equivalent stress value of the key measuring points were measured by the dynamic stress test system. The results show that the dynamic stress of the screen frame is less than the allowable stress, which reflects the rationality of the structure and provides a reference for the optimization design of the relaxation screen. The results show that the dynamic stress test instrument and the finite element analysis are close to each other, which verifies the reliability of the two methods.