Clean liquid fuel was produced from the catalytic hydrogenation of coal tar using two serial fixed beds. Hydrofining catalyst of MoNi/gamma-Al2O3 and hydrocracking catalyst of WNiP/gamma-Al2O3-USY were filled in the first and second fixed beds, respectively. In the initial catalyst screening tests, the typical fixed experimental conditions were as follows: hydrogen pressure of 8 MPa, liquid hourly space velocity of 0.8 h(-1), hydrogen-to-tar volume ratio of 1600, temperature in first fixed bed at 360 degrees C, and temperature in second fixed bed at 380 degrees C. Gasoline (<= 180 degrees C) and diesel (180-360 degrees C) fractions were then separated from the effluent oil. Their fuel indexes were determined to assess the hydrogenation performance. The effect of pressure (6-10 MPa) on the hydrogenation performance was also investigated by keeping other experimental conditions constant. The catalysts showed good stability in activity in the test of catalyst life. The analysis results of the products indicated that raw coal tar could be promisingly upgraded by catalytic hydrogenation in the serial fixed beds. Nitrogen and sulfur contents were greatly reduced from 1.69 and 0.96 wt % in the feed to less than 10 and 50 ppm, respectively, in the products.