The second order asymmetric double screw extruder with mixing element is designed, and the solid model is established by using Solidworks. Based on the finite volume method, the ANSYS/CFX finite element analysis software was used to simulate the movement and processing process of soybean meal in the machine barrel, which was verified by the experiments. Results: when the constant temperature was 80 ℃, the new double-screw extruder produces alternating pressure due to mixing elements, differential asymmetric flow field and volume difference of the first and second stage screw grooves. The material was continuously stretched and compressed and undergoes multiple segmentation and recombination, which improved the compression ability and dispersion mixing ability of the new double-screw extruder.