Abstract: During the process of heavy oil dehydration,the dehydration effect is mainly affected by the factors such as low temperature,the inappropriate proportion of mixing light oil,the wrong place of the input demulsifying agent,too high or too low OWC,added chemical agents,low mixing intensity and etc.Through the analysis of these factors,the dehydration temperature should be set to be 80℃,OWC should be 6.5～7.5m and the mixing intensigy should be increased. which guarantees the successful process of heavy oil dehydration and keeps the water cut within the specified standards.