A preparation method of an electrode impregnation pitch adopts the medium temperature pitch as the raw material and the dephenollized phenol oil as the solvent which passes three processing steps of thermal dissolving, vacuum filtrating and solvent distillation recycling so as to remove the quinoline insoluble matter in the medium temperature pitch, thus leading the weight of quinoline insoluble matter to be less than 0.1 percent of the electrode impregnation pitch product. The yield of the electrode impregnation pitch of the invention can reach more than 80 percent. The used dephenollized phenol oil can be reused and the filter cake can be processed as the heavy asphalt. The whole process needs less equipment and less working procedure with easy control, simple technique and good effect.The invention has an effective method of processing the coal tar pitch can produce 4,000 tons of the electrode impregnation pitches, supposing with the annual process of 5,000 tons of the medium temperature pitch.