The utility model relates to a tail gas purifier for automobiles, which is composed of a gas inlet pipe, an oxidation reduction chamber, a gas exhaust pipe, a communicating pipe and a preheating chamber, wherein the periphery of the gas inlet pipe is enclosed with a cavity which is the preheating chamber. One end of the preheating chamber is connected with the oxidation reduction chamber, and the other end of the preheating chamber is connected with the gas exhaust pipe. The preheating chamber, the oxidation reduction chamber and the inner wall of the communicating pipe are adhered with heat preservation and heat insulation linings. A catalyst carrier soaked with catalysts is arranged in the oxidation reduction chamber. The connecting part between the oxidation reduction chamber and the gas inlet pipe is provided with vent holes. The purifier makes use of heat generated when tail gas conducts oxidation reduction to heat btail gas, so as to achieve the temperature for oxidation reduction. Therefore, the utility model improves purifying effect, makes full use of heating sources and prolongs service life. The utility model has the advantages of convenient use and simple structure.