Facing the double challenges of energy shortage and environmental pollution, development and utilization of biomass energy is of great urgency. In this review paper, the current situation and types of biomass energy are reviewed and discussed based on the world energy crisis and its
environmental problems. As a typical renewable green liquid energy, bio-ethanol, made from plants with rich reserves, could be applied to the field of traffic transportation. Due to the complex structure, variety, and stable nature of plant biomass, cost-effective pretreatment technology has
become an urgent demand in the bio-energy field of current world. At present, various pretreatment methods for enzymatic saccharification of plant biomass have different defects. Therefore, the research on pretreatment technology needs to comprehensively consider the heterogeneity of chemical
composition and structural characteristics of raw material and the pertinence of pretreatment methods.