At the beginning of the tests on application of ethanol gasoline in 2001, Chinese govern- ment promulgated a national standard, GB 18351-2001 “Ethanol Gasoline for Motor Vehicles”. The standard specifies three kinds of ethanol gasoline, namely E10 (90 RON), E10 (93 RON) and E10 (95 RON). There were ethanol gasoline grades (90 RON and 93 RON) and conventional unleaded gaso- line(97 RON) available in the areas where tests were carried out. Vehicle owners were worried about the harmful action of ethanol to their vehicles because of lack of knowledge regarding ethanol fuel, and they only refueled their cars with conventional 97 RON unleaded gasoline. This idea might cause unnecessary costs to customers and could bring about difficulty to the tests as well. Besides, some other technical questions emerged during the experimental application of ethanol gasoline, such as water content, ethanol content in gasoline, etc. Based on the experiences accumulated during the application tests, the national standard GB 18351-2001 “Ethanol Gasoline for Motor Vehicles” was revised. The revised edition is designated as GB 18351-2004. At the beginning of the tests on application of ethanol gasoline in 2001, Chinese government- promulgated a national standard, GB 18351-2001 “Ethanol Gasoline for Motor Vehicles”. The specification specifies the kinds of ethanol gasoline, ie E10 (90 RON) There were ethanol gasoline grades (90 RON and 93 RON) and conventional unleaded gas-line (97 RON) available in the areas where tests were carried out. Vehicle owners were worried about the harmful action of ethanol to their vehicles because of lack of knowledge regarding ethanol fuel, and they only refueled their cars 97 RON unleaded gasoline. This idea might cause not unnecessary costs to customers and could bring about difficulty to the tests as well. , some other technical questions Introduced in the experimental application of ethanol gasoline, such as water content, ethanol content in gasoline, etc. Based on the experiences accumulated during the application tests, the National standard GB 18351-2001 “Ethanol Gasoline for Motor Vehicles” was revised. The revised edition is designated as GB 18351-2004.