In order to develop an effective use of coal liquids, the middle distillate of Wandoan coal liquid obtained by a coal liquefaction plant of 1t/d (Sumitomo Metal Co., Ltd) was hydrocracked under initial hydrogen pressure of 5.9 MPa at 400°C, in the presence or absence of Ni-Mo-Al2O3 catalyst. The raw coal liquid contained mainly condensed aromatic compounds and n-paraffins, and the content of 2 rings aromatics such as naphthalene was major, namely 30.1%. To clarify the behavior of gaseous hydrogen in the process of hydrocracking, 3H labeled gaseous hydrogen was used as tracer. When coal liquid was hydrocracked in 3H atomosphere, 3H atoms were transfered to coal liquid even without catalyst. The catalyst promoted the 3H transfer, and then a small amount of sulfur more accelerated the catalytic activity. The behavior of 2 and 3 rings aromatics in the products indicated that the hydrocracking was proceeded by the hydrogen donation from some donor compounds in coal liquid without catalyst. Furthermore, the hydrocracked products of acridine and carbazole in the products were traced to examine the hydrodenitrogenation process. The most important result obtained was that the hydrodenitrogenation of their compounds were not proceeded in the absence of catalyst but they were hydrotreated rapidly on the catalyst and then hydrodenitrogenated.