Abstract: In view of heavy crude oil has unique feature such as high density, heavy viscosity, high content of colloid, asphaltene and salt content. Bottle test is used to choose effective demulsifier. Influential factors of crude oil electrical desalting are analyzed and operation conditions are optimized using orthogonal experiments. The test result shows that under the operation conditions, the amount of demulsifier is 80 μg/g, the amount of water is 12%, mixing time is 5 min, temperature is 145℃, the strength of electrical field is 1000 V/cm, the retention time is 90 min and three-stage electrical desalting, crude oil's salt content is ≤3 mg/L and water content is ≤0.3%(wt), which accord with current industry standard.