In this study, an improved free surface electrospinning was applied to large-scale production of polyvinyl alcohol nanofibers by utilizing a stepped pyramid stage. Multiple polymer jets were observed to form on the edges of the stepped pyramid stage. The influences of operating parameters (e.g. polymer solution concentration, applied voltage and collecting distance) on fiber diameter as well as productivity were experimentally investigated. Response surface methodology was utilized to obtain a quantitative relationship between selected electrospinning parameters and the average fiber diameters as well as the productivity, and the analysis of variance has been used to the statistical validation of regression models. Adjusted R-squared was found to be 98.79% and 98.55% for the fiber diameter and productivity, respectively. The results indicated that the solution concentration had a statistically significant effect on the fiber diameter and the applied potential influence, largely on the productivity.