Abstract: With the rapid-growing development of RV air-conditioners, horizontal rotary compressors have been widely applied in vehicle-mounted air-conditioning systems owing to their advantages of fewer components, high reliability, low overall height and low center of gravity. Nevertheless, with the accelerated implementation of energy-saving and environmental-protection policies, the application of new refrigerants, novel structures and complex operating scenarios brings increasingly severe technical challenges to compressors. Along with the popularization of R32 refrigerant in RV air-conditioners, reliability failures such as wear at the bearing end and crankshaft root have been exposed during the development of vehicle-mounted horizontal rotary compressors. To solve this problem, this paper identifies the root cause of product failure through theoretical analysis and puts forward an effective solution. Finally, experiments are carried out to verify the effectiveness of the proposed design improvement.