Polyacrylonitrile (PAN) nanofiber paper has the characteristics of high porosity and three- dimensional connectivity. After carbonization, carbon fiber paper can be used in fuel cell proton exchange membrane. Improving the performance of PAN nanofibers helps to obtain high-quality carbon fiber paper. In this paper, carbon nanotube (CNT) was used to reinforce polyacrylonitrile and CNT/PAN nanofiber membranes were prepared by electrospinning. The effects of CNT on the microstructure, thermal stability and conductivity of the fiber membranes were studied. The SEM images and thermal stability of the fiber membranes were analyzed. The results show that when the mass fraction of CNT is 2%, the porosity and specific surface area of the fiber membrane are 86% and 21.1 m²/g, respectively. Compared with the fiber membrane without CNT,the resistance of the fiber membrane is decreased by 40% , and the maximum thermal decomposition temperature increases by 6 ℃ . This study laid a foundation for the preparation of high-performance carbon fiber paper precursors for batteries.