Abstract: A three-way catalytic conversion system for purification treatment of an engine exhaust gas and use thereof, including an oxidation segment containing an oxidation catalyst and a three-way conversion segment containing a three-way catalyst, where the oxidation catalyst is used to catalyze an oxidation reaction of reductive components in the engine exhaust gas with oxygen, the oxidation segment is located downstream of an engine, and the three-way conversion segment is located downstream of the oxidation segment. Further, the oxidation catalyst tolerant to ultra-high temperature is provided upstream of the three-way catalyst so that the engine exhaust gas is treated by the oxidation catalyst first and then by the three-way catalyst, which can avoid the TWC being exposed to high temperature caused by burning (CO, HC), reduce its deterioration, and ensure exertion of function of three-way catalytic conversion of the system, improving the purification efficiency of the engine exhaust gas.