Objective: To study the physical and geometric factors that affect the extrusion effect between particles in the spiral extrusion dewatering device for kitchen waste, and to provide reference for selecting the parameters of the spiral extrusion and dewatering device. Methods: Based on the discrete element method, the state of the extruded particles was analyzed, and the extrusion situation of the material particles in the device was simulated by changing the filling coefficient, spiral speed and inclination angle. Results: When there was some inclination angle in the screw extrusion dehydration device with variable pitch, the filling coefficient increased and the rotation speed up, and the extrusion pressure between the material particles increased accordingly. Conclusion: When the filling rate was 60%, the screw speed was 60 r/min, and the angle was 15°, the extrusion performance of the screw extrusion device could be significantly improved.