With the increasingly stringent fuel consumption regulations and emission standards， many new technologies have been applied to gasoline engines. The application of exhaust gas recirculation （EGR） technology in gasoline engines has become the mainstream. Based on the introduction of high and low pressure EGR system， firstly， the working principle of EGR system is described， and the characteristics of EGR system are analyzed； Then combined with the general curve of gasoline engine， the method of using EGR strategy to improve brake specific fuel consumption （BSFC） is proposed， and the emission reduction effect of applying EGR Technology is analyzed and explained. It is concluded that EGR Technology will be a necessary part of modern gasoline engine technology.