A series of sulfonated polyimides (SPIs) were synthesized by 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTDA), 2,2′-benzidinedisulfonic acid (BDSA) and 4,4′- diaminodiphenyl ether (ODA) in m-cresol. The sulfonation degree of SPI was controlled through the ratio of sulfonated diamine to the non-sulfonated diamine, and the SPI membranes were prepared by a casting method. The chemical structures of SPI membranes were characterized by FT-IR. The properties of obtained SPI membranes were investigated, such as water uptake, ion exchange capacity, proton conductivity and permeability of vanadium ion. The proton conductivities of SPI membranes are ranged from 0.012 to 0.051 S/cm, and the permeabilities of vanadium ion are one or two orders of magnitude less than that of Nafion® 117 (1.80×10-6cm2/min ). Experimental results showed that SPI membranes are potential candidates for vanadium redox flow battery.