Abstract: In view of the problems of low screening swing frequency, low screening rate and low screening efficiency of the two-layer and three-layer screen-type zanthoxylum screening machines, a four-layer sieve type zanthoxylum screening machine was designed. The top sieve was connected with the second sieve, the third sieve was connected with the bottom sieve. The two sets of connecting devices driven by the eccentric wheel and pulled by the connecting rod moved in opposite directions when swinging, thereby reducing the swing unbalanced moment and improving the screening of the highest swing frequency. And the design of the whole machine structure and key components was carried out. The vibration modal simulation of the frame and the four-layer screen was carried out. The stability of the frame and the screen surface, the parameters of the swing mechanism, the inclination angle and the swing angle of the screen surface were analyzed. The screening stability and screening performance were tested. The results showed that the first-order vibration frequencies of the frame, top screen, second screen, third layer and bottom screen of the screening machine were 9.7 Hz, 9.9 Hz, 11.7 Hz, 9.3 Hz and 9.4 Hz, respectively. The natural vibration frequency of the whole machine was about 11.8 Hz. The higher the screening frequency was, the greater the maximum feeding amount and screening efficiency were. When the swing angle of the screening machine was 2.77°, the inclination angles of the top and bottom screens were 6.95° and 8.12°, respectively. The optimal screening frequency was 9.0 Hz. The maximum feeding amount of screening was 792 kg/h, and the screening efficiency was 559 kg/h, and the net rate and loss rate of zanthoxylum shells were 98.1% and 3.1%, respectively. The net rate and loss rate of zanthoxylum seeds were 94.1% and 4.2%, respectively.