The invention provides a recovery system of low-order coal pyrolysis oil gas. The recovery system comprises a cyclone dust collector, a filter dust collector, washing equipment, an electrical tar precipitator, adsorption equipment and a desulfurizing tower, wherein the washing equipment comprises an ammonia water storage tank, a tar washing tank and a gas-liquid contact vertical pipe which is positioned above the tar washing tank; the adsorption equipment is internally filled with one or more of pyrolytic semi-cokes, cokes, sawdust, granular activated carbon, activated carbon fiber, silica gel, activated aluminum oxide and molecular sieve. According to the recovery system provided by the invention, a dynamic wave washer is adopted, the structure is simple, the manufacturing cost is low, the energy consumption is low, the operation flexibility is large, and the gas-liquid mass transfer effect is good; due to the additional arrangement of a soft connecting pipe wall and a vibrator/an oscillator, the situation that a pipeline is blocked as tar is condensed on the pipe wall can be effectively avoided; through an oil gas product recovery technology adopted by the invention, and by arranging a hydrogen sulfide adsorption device and a dewatering device, hydrogen sulfide and water vapor in pyrolysis gas can be adsorbed, and the problems that due to the condensation of tar mist, VOCs (Volatile Organic Compouns) and the water vapor in the pyrolysis gas, pipeline equipment is corroded, and long-distance transportation requirements are difficult to meet are effectively solved.