The invention discloses a comprehensive utilization method of coal tar. The method comprises steps as follows: coal tar and a pretreating agent enter a pretreating reactor and are mixed uniformly andsubjected to sedimentation-filtration treatment, insoluble substances are separated out, and purified coal tar is obtained; the obtained purified coal tar and hydrogen are mixed, and then a mixture enters a boiling-bed hydrogenation treatment reaction area for hydrogenation treatment; reaction oil obtained in the boiling-bed hydrogenation treatment reaction area sequentially passes through a fixed-bed hydrogenation pretreatment reaction area and a fixed-bed hydrogenation treatment reaction area which are connected in series, and after reaction effluent obtained in the fixed-bed hydrogenation treatment reaction area is separated, gas, naphtha, diesel, wax oil and tail oil are obtained. According to the method, the process is simple, all that is required is to simply improve an existing device, so that running period of the device can be substantially prolonged, and the maximum utilization efficiency of a catalyst can be realized.