The second-generation fuel ethanol production uses lignocellulosic wastes as a raw material, which is abundant and typically treated as waste, addressing the issue of “competing for food with people” caused by the first generation fuel ethanol and showing great significance to national energy security and social sustainability. Lignocellulosic wastes used in the second generation fuel ethanol production requires pretreatment by biological, physical or chemical methods to disrupt its recalcitrant structure and enhance its enzymatic digestibility. The polysaccharide components of the pretreated lignocellulose are then degraded by enzymes into fermentable monosaccharides that can be converted into ethanol by fermentation microorganisms. Currently, many pretreatment methods as well as strategies for enzymatic hydrolysis and fermentation have been developed for the purpose of biomass conversion. Nevertheless, the key to foster the cellulosic ethanol industry is still figuring out how to effectively disrupt lignocellulosic structure at a low cost with a low energy consumption. This chapter reviews and evaluates a variety of lignocellulose pretreatment methods developed in recent years, including advantages and drawbacks, pretreatment mechanisms, and offers a summary of the current status of the cellulosic ethanol technologies. Furthermore, this chapter also discusses processes of enzymatic hydrolysis and fermentation for fuel ethanol production, as well as a detailed analysis of many factors affecting the process performance. Moreover, the bottleneck of the lignocellulosic ethanol production and future perspective are discussed.