In order to improve the lowspeed performance and maximum power of a 2.0 L turbocharged engine, a compound supercharging system composed of electric supercharger and turbocharger was proposed. The turbocharger was rematched and the engine compression ratio was optimized. The simulation model of compound supercharging system was established by GTPower software, which would be used for the selection of compound supercharging system and the prediction of engine performance. Finally, the design scheme was determined and the verification test was carried out. The bench test shows that the compound supercharging system can significantly improve the lowspeed torque, transient response and maximum power of engine. The compound supercharging system therefore provides a feasible technical direction for the development of high performance engine.