The invention relates to a device for dedusting high-temperature coal gas through circulating oil washing and a process flow of the device, and effectively solves the problems that the high-temperature coal gas dedusting efficiency is low, continuous large-scale production cannot be achieved, and the operating cost is high. In order to solve the problems in the prior art, according to the technical scheme, the device comprises a cyclone separator, a particle bed dust remover, an oil gas heat exchanger, a fractionating tower, an oil gas cooler and an oil filter, wherein the oil filter comprises a coal gas outlet, an oil inlet, a top oil gas sprinkling device, a middle oil gas sprinkling device and a coal gas inlet distributor; the coal gas outlet is formed in the top of the oil filter; the oil inlet is formed in the side wall of the oil filter; the top oil gas sprinkling device, the middle oil gas sprinkling device and the coal gas inlet distributor are sequentially arranged inside the cavity of the oil filter from the top to the bottom; the cyclone separator, the particle bed dust remover, the oil gas heat exchanger, the fractionating tower, the oil gas cooler and the oil filter are mutually connected. Through the certain process flow, the high-temperature coal gas is washed.