Abstract: Membranes of ZSM-5 zeolite were obtained by one step in situ hydrothermal synthesis. XRD and SEM micrographs were used to characterize these membranes. The membranes were used for the separation of ethanethiol from n-hexane. It was shown from the result that：the desulfurizing effect decreased with increasing permeation rate；and the rejection performance was enhanced after the membranes were loaded with Cu2+. However，high concentration of Cu2+ decreased the permeation rate. It was also found that at a higher operation temperature，the permeation rate increased while the desulfurizing effect decreased.