Abstract： Due to the tight space on the offshore platform, the traditional gravity oil and water separation method has a long residence time and a large size of the equipment, which affects the development cost of offshore oil field. It is essential to study compact and high efficiency crude oil processing equipment to reduce platform space and block weight. The electric coalescence crude oil dehydration is a kind of high efficiency technology developed in recent years. The theory and technology background of electric coalescence technology are introduced. The current technology development situation is analyzed. Finally the application prospect of the technology is given.