Abstract: In this paper, a design method for a profile die runner was developed based on orthogonal test and numerical simulation. The procedure was as follows: the main parameters of the extrusion flow were defined as the experimental factors, a simulation model was formulated using Inventor software, the situation of plastic melt flowing in the profile dies were simulated through Polyflow as a finite element analysis software of CFD, selecting appropriate criterion to evaluate the results of orthogonal test and optimizing the parameters repeatedly，then the reasonable parameters were gained. Based on this method, column-shaped extrusion die for Wood-plastic composite materials was designed and optimized, eventually the ideal design results were obtained.

Key words: orthogonal test, profile, die, numerical simulation, wood-plastic composite, runner