The invention relates to an inlet circulating gas cooler of a coke dry quenching boiler and an operation method thereof. The inlet circulating gas cooler comprises a gas path device, a water path device and a control device, wherein the gas path device comprises a gas inlet chamber, a heat exchanger gas chamber and a gas outlet chamber; the gas inlet chamber is communicated with the heat exchanger gas chamber and is used for feeding gas and guiding the gas into the heat exchanger gas chamber; the heat exchanger gas chamber is used for performing heat exchange on the gas; the gas outlet chamber is communicated with the heat exchanger gas chamber and is used for guiding out the gas; the water path device comprises a water inlet pipe, a coiled pipe, a water collection pipe and a water discharge device; the water inlet pipe is communicated with the water collection pipe and is used for feeding water and guiding the water into the water collection pipe; the water collection pipe is communicated with the coiled pipe and is used for guiding the water into the coiled pipe; the coiled pipe is communicated with the water discharge device and is used for guiding the water to the water discharge device; the water discharge device is used for guiding out the water in the coiled pipe; the control device is in control connection with the gas path device and the water path device so as to realize different operation modes. The inlet circulating gas cooler has the obvious effects that the inlet circulating gas temperature of the coke dry quenching boiler is reduced, the desalted water consumption and deoxidized steam consumption of the coke dry quenching boiler are reduced, and the coke dry quenching rate is improved.