Medium-temperature coal tar needs to be purified before hydrogenation because harmful substances are contained. The removal of solid impurities, desalination, dewatering and demetallization of Northern Shaanxi medium-temperature coal tar through filtration and electric desalination were studied in this paper. Results showed that solid impurities (SI), especially toluene-insoluble (TI) and quinoline-insoluble (QI) are effectively removed. The water content of the treated medium-temperature coal tar was finally reduced from 1.32 wt% to 0.19 wt%, and salt content from 63.8 to 2.4 mg/L. Similarly, the impurity atoms such as S, N, O, Fe and Ca were efficiently removed.