Abstract: The electrospinning of zein was performed with glacial acetic acid, and the morphology of the zein fibers was investigated by scanning electron microscopy. Box-Behnken experimental design was employed with three main influential parameters, i.e. zein mass concentration, electric field intensity and flow rate, as the independent variables and the diameter of the zein fibers as the investigative object. The multiple regression model was set up by regression analysis. The results indicate that the zein mass concentration has the most significant influence on the diameter of the fibers, and the next is the interaction item of the electric field intensity and flow rate. The observed responses are in close agreement with the predicted values of the model. By using of response surface design, the process of experiment at design was simplified and the condition of the desired fiber diameter could be obtained easily according to the model. This has a great significance to produce nanofibers via electrospinning.