A novel fibrous polymer electrolyte membrane was produced based on polymethyl methacrylate/polyacrylonitrile (PMMA/PAN) blend. This was achieved through optimization in the loadings of the two polymers and electrospinning method. Consequently, the effect of PMMA on the ionic conductivity was assessed. A quantitative relationship between ionic conductivity and the important parameters including voltage, solution concentration, and PMMA content was determined. The response surface method (RSM) was employed to obtain the quantitative relationship and to determine the ion conductivity of PAN/PMMA electrospun membrane. Analysis of variance technique was used to study the importance of parameters and their interactions. A regression model was applied to determine the most influential factors on the ionic conductivity and to find the maximum ionic conductivity of the electrolyte membrane as an optimal result. The average fiber diameter was in the range of 206-367 nm, and the membranes were associated with high porosities between 50 and 91 %, and the electrolyte uptakes were in the range of 285-460 %. For all samples, the ionic conductivity of gel polymer electrolytes at 25 degrees C was above the 1 mS/cm. The ionic conductivity changed with the voltage directly and with the solution concentration inversely. According to the results, the ionic conductivity showed its dependency with the PMMA content, increasing with the PMMA content up to 50 % and smoothly decreasing with PMMA further increases. Some important interactions between the parameters were also detected.