An experimental study was carried out on the synergistic effect of electric supercharging and exhaust gas recirculation （EGR） on engine power and economy on a 1.5 L direct injection gasoline engine with exhaust gas turbocharging. The results show that under full load, the maximum EGR rate promoted by electric supercharging decreases with the increase of rotational speed, and increases by 17.7%, 15.2%, 13.84% and 0 respectively under the four experimental rotational speeds. Under partial load, the maximum EGR rate promoted with electric supercharging decreases with the increase of load and rotational speed. Under six experimental conditions, the maximum EGR rate is increased by 23.63%, 30.31%, 0, 14.09%, 19.74% and 0 respectively. Under full load and at three lower rotational speeds after the intervention of electric supercharging, the brake specific fuel consumption (BSFC) is reduced by nearly 10%. At the highest speed, exhaust gas turbocharging completely replaces electric supercharging. In two groups of working conditions under partial load and after the intervention of electric supercharging, the maximum BSFC is reduced by 10.8% and 8.4%. It is concluded that the reasonable application of electric supercharging to promote the highest EGR rate can improve the fuel economy and maintain higher power performance of the engine.