The preparation conditions of a polyacrylonitrile (PAN) ultrafiltration membrane for wastewater treatment was investigated. The PAN membranes were prepared by the phase-inversion process in a water gelation bath using casting solutions of varying compositions of PAN/polyvinylpyrolidone (PVP)/N,N-dimethylacetamide (DMAc) and showed a molecular weight cut-off of 50,000-500,000. Especially, the membrane prepared from casting solutions with PVP and annealed at 80degreesC in water showed high water flux with a molecular weight cut-off of 500,000. Furthermore, the composite membranes of PAN-acrylic acid, prepared by the photo-induced graft polymerization technique, improved high performance.