The bench test was carried out on the EFI gasoline engine without changing the engine parameters and the exhaust noise, exhaust temperature and emission characteristics of ethanol gasoline (E20W) and pure gasoline (E0) were compared and analyzed. The test results show that the exhaust noise of E20W at low speed is lower than that of pure gasoline and the maximum reduction is 7.4% compared with pure gasoline. At medium and high speeds, the difference of exhaust noise between them cannot be identified. In addition, the exhaust temperature of E20W is higher than that of pure gasoline with an average increase of 5.3%.The gasoline engine fueled with E20W can significantly reduce HC and CO emissions with an average reduction of 10.4% and 33.6% respectively, but NO_x and CO₂ emissions increase. On the whole, the hydrous ethanol gasoline E20W can be applied to test engine directly and can reduce exhaust noise and emissions.