Abstract: Positively charged nanofiltration membrane of polysulfone/Al2O3 composite was prepared by a immersion process. The influence of main technical conditions during membrane preparation on membrane transport parameters was studied including pure water flux，Na+ transport parameter and streaming potential. The morphologies of membrane surface and cross-section were observed by SEM. The structure of membrane surface active layer and and its formation mechanism were analysed by FTIR. In the enrichment of gold from thiourea leaching solution，the prepared membrane has a better rejection performance. At 0.65 MPa and 20℃，the rejection of gold(Ⅲ) could be reached to about 88%—95%.