Abstract: The oil pollution of wastewater containing oil in tidal areas of the Changjiang Estuary and Hangzhou Bay is calculated by using the Princeton Ocean Model(POM),which is a three-dimensional model.The oil concentration distributions in winter and summer around the sewage outfall of Zhonggang,Xinhuo and Jinshan,located on the north coast of Hangzhou Bay,are numerically simulated.Calculation results show that the semidiurnal tidal waves are on the dominant position and the main component of tidal field is the M_2 tide in the Changjiang Estuary and Hangzhou Bay;under the action of the Changjiang runoff,the tides make a clockwise whirlpool,which is favorable to conveying the pollutants towards outside of Hangzhou Bay.In the aspect of conveying the pollutants,Zhonggang is superior to the others and Xinhuo is better than Jinshan.Under the present calculation conditions,selecting the initial oil concentration around the sewage outfall as 10mg/L is suitable for attaining the third class of the national water quality standard.