The invention belongs to a system for treating coke oven exhausted contaminants. The system comprises a percolator, a water tank, a dehydration tank, a filter paste tank and a diaphragm pump, wherein a row of spraying nozzles which are used for spraying a hydrogen solution are arranged at the internal upper end of a flue communicating with a fume inlet, the fume inlet communicates with the lower end of the inner side of a fume scrubber, a fume outlet of the fume scrubber communicates with the internal upper end of a fume washer, the internal lower end of the fume washer communicates with the internal upper end of a gas washer, a gas outlet of the gas washer communicates with the dehydration tank through an 8-shaped cyclone pipe, the upper end of the dehydration tank serves as a fume exhaust outlet, an upper water outlet of the percolator communicates with an upper water inlet of the fume washer and a lower water inlet of the gas washer separately through water inlet pipes, and a lower water outlet of the percolator communicates with the internal upper end of the filter paste tank through the diaphragm pump. The system can be used for carrying out effective cooling, dedusting, denitration, desulfuration and deacidification treatment on harmful flue gases exhausted from a coke oven, and the operating cost is reduced; and the system has the advantages that the structure is simple, the performance is stable, the mounting and repairing are convenient, and the contaminant treatment effect is good.