The invention provides a three-way catalytic reactor protecting system for an automobile, which belongs to the technical field of vehicles. The technical problems of poor purification effect, short service life and the like of a traditional automobile three-way catalytic reactor are solved. In the three-way catalytic reactor protecting system for the automobile, a vehicle comprises an exhaust pipe and a three-way catalytic reactor, wherein the exhaust pipe is communicated with an engine exhaust manifold; the three-way catalytic reactor is connected to the exhaust pipe. The protecting system comprises an electrically controlled unit (ECU) and a sensing element which is arranged on the exhaust pipe and can detect tail gas temperature, wherein the sensing element is connected with the ECU. Acooling device capable of reducing the tail gas temperature in the exhaust pipe is arranged on the exhaust pipe between the exhaust manifold and the three-way catalytic reactor and is connected with the ECU through a control mechanism capable of controlling the cooling device to cool tail gas forcibly. By reducing the tail gas temperature, the three-way catalytic reactor can be effectively protected. At the same time, the three-way catalytic reactor protecting system for the automobile has the advantages of low energy consumption, high environmental friendliness and the like.