To solve the problems of low production, needle blockage, and Taylor cone stability, a self-made free surface electrospinning (FSE), namely spherical section FSE (SSFSE), is developed to obtain high-throughput production of nanofibers, which can use solution reservoirs with different radii. The surface morphology of polyacrylonitrile (PAN) nanofibers fabricated using SSFSE is investigated by scanning electron microscopy (SEM). According to the SEM data, response surface methodology (RSM) is used to model and optimize the SSFSE process for evaluating the effect of spinning parameters on the nanofiber diameter, and the established RSM model is applied to determine the optimal spinning parameters. The results reveal that the solution reservoir radius and the applied voltage both have great effects on nanofiber diameter, and nanofibers with the highest quality and yield are achieved using a solution reservoir with a radius of 25 mm at 40 kV. In addition, the electric field distributions produce in the SSFSE processes with solution reservoirs of different radii are simulated by Maxwell 3D to study the preparation mechanism of the SSFSE device. The electric field simulation results are in keeping with the experimental data and indicate that these five SSFSE devices have the potential to increase the yield, and the device using a solution reservoir with a radius of 25 mm provides the highest quality and yield of nanofibers. (C) 2020 The Author(s). Published by Elsevier B.V.