Abstract: Polyethylene glycol membranes with different molecular weight cut-offs under intermittent cross-flow condition are used to treat oil wastewater,and their experimental conditions including pressure,temperature on permeate rate and removal rate of chemical oxygen demand (CODCr) are studied in the paper.The results show the permeate rate of ultrafiltration membrane can be influenced by pressure and temperature,and pressure is chosen between 0.3～0.7　MPa to the PEG with molecular weight cut-offs of 8　000 and between 0.7～1.0 MPa to the PEG with molecular weight cut-offs of 2　500,and temperature is chosen between 25～32　℃.The UF membrane under intermittent cross-flow operating mode can remove up to 93% COD.

Key words: oil wastewater, ultrafiltration membrane, intermittent cross-flow, permeate water, CODcr