Feature: On bottom of the separating tower there are inlet of crude fatty acid methyl ester and outlet of wash water. On top there are outlet of crude fatty acid methyl ester and inlet of wash water. There is oil-water separation section on the bottom of separating tower. It achieves the continuous production of biodiesel washing, and improves the automation level of the production process. The washing tower with special structure strengthen the oil and water contact, changes the backward process of kettle type washing, washing time is significantly shortened. It solves the problem of acid return by water wash, greatly saves the process water, reducing the pressure on environmental protection.