In this study, Dehydrochlorinated poly (vinyl chloride) Membrane was directly sulfonated with chlorosulfuric acid(CSA). The structure of sulfonated PVC (SPVC) was confirmed by Fourier-transform infrared (FT-IR). For quantitative analysis of the chemical composition, the X-ray Photoelectron Spectroscopy (XPS) was used. The ion exchange capacity, electrical resistance and water uptake were also measured to evaluate the membrane performance.