Abstract: By using immersion method, the corrosion and swelling of the NBR and PTFE plastic fuel pipe were investigated with ethanol and 0# diesel soaked for 672 h under normal temperature. The nitrile rubber Teflon pipe inner surface and the microscopic changes of the NBR and PTFE plastic fuel pipe were analyzed by using scanning electron microscopy .The test results showed that: after soaking 672 h at room temperature, part of the substances of rubber and plastic were dissolved in ethanol solution; Ethanol have polarity effect on rubber and plastic, the surface of NBR fuel pipe in ethanol had a blooming phenomenon and the “blooming” effect is obvious increased with time. The surface color of Teflon surface becomes shallow after soaking in ethanol; The results showed that corrosion of rubber and plastics occurred on diesel engine fuel system with ethanol, according to the microstructure, diesel engine fuel system cannot be used with ethanol for long term at present stage.