Hydrophilic polyvinyl alcohol (PVA) as a membrane material was employed to prepare ultrafiltration (UF) membranes. The PVA-based hydrophilic UF membranes could be directly made by immersion precipitation through modified PVA with controlled hydrophilicity. The impact of parameters such as the acetalizing degree of PVA, composition of the casting solution, addition of salts in the coagulation bath and conditions of membrane preparation on performances of the modified PVA membranes was investigated. The foremost factor that may affect the formation of membranes was the hydrophilicity of modified PVA. The results showed that the modified PVA membrane exhibited a high level of water permeation along with good retention of BSA. Due to good hydrophilicity of the modified PVA UF membrane, there is a tendency to relieve protein fouling effectively.