Lignocellulose that is the primary polysaccharide of plant cell wall has been received considerable attention as a main feedstock for bio-refinery process such as bio-fuel production. The enzymatic hydrolysis of lignocellulose to soluble sugars is considered to be one of the environmental friendly processes for bio-ethanol production. But the spontaneous crystallization of cellulose due to the chemical uniformity of glucose and high degree of hydrogen bonding can form densely packed micro-fibrils which are inaccessible to cellulolytic enzymes. Therefore, efficient and cost-effective methods for the degradation and fermentation of lignocellulosic biomass to ethanol are required. In this study, for deconstruction of biomass, the ionic liquid was used as a pre-treatment medium, and the effective degradation and assimilation procedure was investigated. This effective process has been named as 'Ionic liquid-based Consolidated Bio-Processing (i-CBP)'. In this process, pretreated biomass by ionic liquids would be easily hydrolyzed to glucose and directly converted to ethanol by functional transgenic yeasts that were simultaneously displayed four kinds celluloses, endoglucase (EG), cellobiohydrolase (CBH I & II), and beta-glucosidase (BGL) on the cell surface. Research findings from these studies will be presented.