The paper prepared polysulfone ultrafiltration membranes via phase-inversion method by using LiCl, nano-silica, methyl methacrylate, glycerol, polyvinylpyrrolidone as additive reagent and N, N-dimethyl acetamide as solvent. The effects of the additive reagent on the membrane performance were evaluated by water flux, contact angle, scanning electron microscopy(SEM). The results indicated that the addition of nano-silica and LiCl improves the structure and morphology of membrane, and also improves the performance of membrane. At the same time the pore size and porosity are increased. Nano-silica greatly increases the water flux and hydrophilicity of membrane, LiCl improves the rejection coefficient of membrane to humic acid.