Computer simulation technology is used to simulate the injection molding of a network security controller, and the flatness is optimized and analyzed. By comparing and analyzing the injection molding results of three injection schemes: center injection, long-side injection and short-side injection, the optimal injection scheme is short-side injection. Taking process parameters as independent variables and flatness as objective variables, orthogonal test was designed and data was analyzed. The results show that the influence of holding time on flatness is extremely significant, the influence of melt temperature and cavity temperature on flatness is significant, and the influence of injection time on flatness is not significant. The optimum combination of process parameters is A₃B₁C₃D₁. Through process optimization, the flatness is reduced to 1.070 7 mm, which is 28.2% lower than that of the initial process. The actual mold test results are qualified, which verifies the feasibility of this optimized process.