The velocity and pressure fields of the fluid in the twin-screw extruder were studied using FEM. The specific energy consumption of various operations was obtained by post-processing. The experiment was designed using the rotatable and central composite method. The reason for the existing differences between the simulation and experimental results was analyzed, and the simulation results were corrected. The BP algorithm was trained based on the simulation and experimental results. The extruding system model of twin-screw extruder was built, and could be used to quantitatively predict the specific energy consumption of the extruder.