The invention relates to the field of coal tar recovery, in particular to a recovery system of coal tar in pyrolysis gas. The recovery system comprises a primary cooling tower, a heat exchanger, a secondary cooling tower and a solvent evaporator, wherein the primary cooling tower is used for recovering heavy coal tar in the gas; the shell side of the heat exchanger communicates with an outlet of the primary cooling tower; the gas from the primary cooling tower exchanges heat with heat exchange mediums in the pipe side of the heat exchanger so that the heat in the gas can be recovered; the secondary cooling tower communicates with a shell side outlet of the heat exchanger; a first reverse spraying device is arranged in the secondary cooling tower to spray a solvent on the gas from the heatexchanger, so that light coal tar in the gas is recovered; the solvent evaporator is internally provided with a heating component communicating with the pipe side of the heat exchanger to enable the heat exchange mediums to enter the heating component to serve as a heat source; and the solvent evaporator communicates with the secondary cooling tower and heats and evaporates the solvent sprayed outof the secondary cooling tower through the heating component, so that the solvent is recovered. According to the recovery system of the coal tar in the pyrolysis gas, the heat in the pyrolysis gas isreasonably recovered, and the thermal efficiency of the coal pyrolysis process is improved.