Abstract: The energy efficiency and ethanol output are the mayor indicators of the biomass-to-ethanol process. In this paper the simulation result of energy efficiency from lignocellulosic biomass to ethanol was introduced，and the process simulation result was used to estimate the energy efficiency of the different biomass raw materials and different processes. According to the energy efficiency estimation，the process and biomass feed，such as saccharification and fermentation time，distillation process，would be devised more efficiently.