Abstract: Studies indicated that the reason for demulsion difficulty of Tahe emulsified crude oil was closely related to residual chemicals, solid particles, resins and asphaltenes in the crude oil. Therefore, we developed a demulsifying technology were for the crude, including excellent performance chemicals, such as demulsifiers, wetting agents, and neutralizer as well as the supporting treatment technologies of washing and electrostatic field. The results show that the washing pretreatment of oil could reduce the dosing of chemicals and provide a lower load for the subsequent process, and benefits for the smoothly running of electric dehydrator. After washing, the subsequent chemical demulsification and electrostatic dehydration technologies can reduce the water content to less than 1%, satisfied with the requirement of Tahe oilfield.