Although needle-free roller electrostatic spinning technology has the advantages of higher output than traditional needle electrostatic spinning, it has the problem of uneven distribution of electric field and poor quality of filaments. The emphasis of this study is to solve the non-uniform distribution of the electric field of roller electrostatic spinning so that it can produce high-quality nanofibers. The electric field analysis shows that the electric field distribution is most uniform when (1) ring electrode is connected to 5kv and parallel electrode is connected to 11kv, and (2) auxiliary electrode is connected to -700v.The finite element analysis of the electric field shows that the auxiliary electrode increases the electric field intensity in the spinneret area. The auxiliary electrode in needleless roller electrostatic spinning technology can be used to develop high efficiency and low energy consumption nano-fiber production system.