The invention relates to an electrostatic coalescer with high efficiency, which is a piece of compact equipment for the electrostatic dehydration of crude oil emulsion with high efficiency, and is applied for the crude oil dehydration in the production process of oil fields. The invention is characterized in that: the invention comprises a housing, which comprises a coalescence part arranged vertically and a sedimentation and separation part arranged horizontally; the coalescence part is a vertical cylinder shaped structure with a cylinder shaped electrode assembly arranged inside; the sedimentation and separation part is a horizontal tank structure arranged below a dehydrator, with an emulsion distribution device, a spoiler and a staggered corrugated coalescing plate arranged inside. A high voltage transformer is arranged on the sedimentation and separation part and is connected with the cylinder shaped electrodes by a high voltage insulated cable. The cylinder shaped electrodes are covered by a compact insulation layer which can reduce leakage current and prevent the short circuit among the electrodes. The distance among the cylinder shaped electrodes is small, so a narrow runner is formed, and high strength electric field is formed in the narrow runner. The invention has the advantages that: the crude oil emulsion successively experiences the effects of electrostatic coalescence, staggered corrugated coalescing plate coalescence and the eddy current coalescence of the spoiler; the contained water drops grow bigger; the settling velocity is accelerated, and the rapid separation between crude oil and water is realized.