The paper analyzed the research background of ethanol energy gain, its latest developments in the world and research statue in China. Furthermore, based on the lifecycle analysis, the paper calculated the net energy value and energy output-input ratio of wheat fuel ethanol, and evaluated the energy gain of wheat fuel ethanol in China. The main conclusions are as follow: If the energy of byproduct was not being calculated, The Net energy values in old and new technology were -17022 MJ/t and -11778 MJ/t fuel ethanol, and the values of R were 0.64 and 0.72, respectively. If the energy of byproduct was being calculated, The Net energy values in old and new technology were 2271 MJ/t and 11249 MJ/t fuel ethanol, and the values of R were 1.05 and 1.27, respectively. The energy gains, which were significantly improved by the new technology, in old and new technology are both positive benefits according to the economic benefit of energy. Compared with the corn fuel ethanol production in America, with the calculation of byproduct’s energy, the net energy values in new and American technology were 11249 MJ/t and 7457 MJ/t fuel ethanol, and the values of R were 1.27 and 1.34, respectively. R in wheat fuel ethanol is lower than in corn fuel ethanol due to higher conversion in corn relative to wheat. Chinese technology for the production of wheat fuel ethanol (new technology) has greater net energy value in comparison with American technology, which is because the advantages for comprehensive utilization of wheat fuel ethanol in China (23027 MJ/t ethanol) were evident relative to the corn fuel ethanol production in America (5078 MJ/t ethanol).