Supercapacitors have great potential in the hybrid fuel automobile market because of their high power density and fast charge and discharge, in which the working electrolyte of supercapacitors is the key to determine their performance. Optimization and preparations of poly(vinylidene difluoride)-hexafluoropropylene/poly(methyl methacrylate) (PVDF-HFP/PMMA) gel polymer electrolyte membranes for supercapacitors based on Design Expert 8.0 software are described. The range of conditions is determined by monofactor analysis. The optimal preparation conditions are obtained by response surface simulation optimization.