Water blended with ethanol can decrease its freezing point effectively and reduce the application difficulty of engine water injection in cold winter. In order to investigate the effect of ethanolwater mixing injection on water injection of gasoline engine, the spray characteristics of ethanol solution were studied in constant volume bomb based on different mixing proportions and the bench test was conducted based on a 1.5 L TGDI engine with port water injection. The results showed that the spray penetration decreased and the atomization obviously improved with the increase of ethanol ratio. Besides, water blended with ethanol could reduce both gasoline and water consumption, improve thermal efficiency, reduce CO and THC emissions, and mitigate the crankcase pressure rise caused by water injection.