The CNC cutting surface of 18 kg/m3-EPS material was studied based on the dualistic orthogonal regression experimental design and the analysis method of signal-to-noise ratio test.The different effect proportions of the spindle speed, axial feed, cutting width and radial feed speed on the cutting surface quality of EPS were determined.Under the joint action of the other factors, the impact of one factor on the cutting surface quality of EPS was analyzed in detail by integrating the image processing function of the SPSS software, and the optimal cutting parameters for each factor were found out.The dualistic expression for the CNC cutting surface was obtained by using the data handling function of SPSS software, which offering reference for EPC CNC cutting machining.