The electric field coal tar purifying process includes the technological steps of preparing mixed oil, the first stage of electric purifying, the second stage of electric purifying, the third stage of electric purifying, draining waste water, etc. The experiments show that the coal tar purifying process of the present invention is superior to available coal tar purifying process, and has the advantages of simple technological process, low running cost, high purifying rate, etc. The present invention can reach coal tar purifying rate over 95 %, and the purified coal tar may be used in producing gasoline and diesel oil through hydromodification with no corrosion to the production apparatus, no catalyst poisoning, no blocking of the reactor bed layer and long production apparatus running period.