Engine power performance of fuel economy and emission characteristics with a JL368Q engine run on ethanol/ gasoline blends was experimentally investigated. The results show that with the same structure and parameter of the engine, at the low speed, the power output or torque of blended fuels are almost similar to that of 93 # gasoline. But with the speed increasing, the E15W and E50W power outputs are lower than that of 93# gasoline while E30W remains the same. The brake specific fuel consumption of E15W is lower than that of gasoline about 0.35%. With the increase of ethanol volume fraction in the blended fuel, the specific fuel consumption increases gradually. When fueled with ethanol/ gasoline blends, the engine NOx emission increases and CO emission decreases. E30W gives the lowest CO emission in this test. With the increase of ethanol volume fraction, HC can be improved gradually.