This paper summarizes our research activities to produce nanoscopic fibrillated product from lignocellulosic biomass using mechano-chemical treatment. Hydrothermal and ozone pretreatment were effective to loosen the cell wall structure, resulting in the improvement of mechanical fibrillation. Characterization of thus-obtained products was conducted, showing sub-micron and/or nanoscopic fibrous morphology, high surface area and high enzymatic digestibility. The effect of chemical composition of the fibrillated product on the adsorption and degradation behavior of various cellulase was investigated by Quartz Crystal Microbalance(QCM). The relationship between the aspect ratio and intrinsic viscosity for the fibrillated product with high aspect ratio was also investigated. The fibrillated product was applied as the reinforcement for nanocomposites and various surfactants were attempted to improve the distribution of the fibrillated product in polymer matrix.