The utility model discloses an oil washing of low order pyrolysis of coal gas purifies oil washing tower, including the lower column, the top of lower column is provided with the upper column, and the top of upper column is provided with the top of the tower cooler, and the upper portion of top of the tower cooler is equipped with the gas collection ware, and the top of gas collection ware is the clean gas outlet, is provided with pyrolysis gas tedge on the upper cover of lower column, and the lower part interlude of lower column is equipped with pyrolysis gas import pipe, has seted up the import of pyrolysis gas in the part of pyrolysis gas import pipe interlude in the lower column, and the bottom of lower column is equipped with the export of washing miscella, all is equipped with the flushing oil distributor in lower column and the upper column. The utility model relates to a rationally, simple structure, operation safe and reliable, can carry out the desorption with the semicoke dust that contains in the low order pyrolysis of coal gas to retrieve coal tar simultaneously.