In the forming process of junction box, in order to understand the influences of different factors on the forming quality of junction box and obtain the optimal forming parameters, the finite element model was established by Dynaform, and combining with Design-Expert software to design the response surface test, and a polynomial regression response model for maximum thinning rate and maximum thickening rate was obtained by experiments. Then, the influence degrees of virtual blank holder force, die clearance and friction coefficient on the maximum thinning rate and the maximum thickening rate of workpiece were further determined, and the maximum thinning rate and the maximum thickening rate were optimized and solved by the non-dominated sorting genetic algorithm with elitist strategy (NSGA-II)to obtain the optimal process parameters as the blank holder force of 21400 N, the die clearance of 1.25 mm and the friction coefficient of 0.08. Simulation experiments were conducted by Dynaform, and the results were validated in the actual production. The study result provides a theoretical basis for the actual production of junction box.