Based on an SI electronic-controlled engine，hydrogen generator and electronic controlled unit were developed， the control strategy for fuel switching and hydrogen mixture mode were set up to realize a smooth transition in the period of fuel switching and an automatic operation under hydrogen mixture mode. Moreover, components measurement of hydrogen mixture online and its effects of mixture concentration on performance of SI engine were performed．The results indicate that besides hydrogen and monoxide carbon, certain amount of methanol steam was found in hydrogen mixture and they account for 23.3%~46%，11.6%~23% and 31%~65% respectively. In addition，the fuel economy is also improved power with gasoline.