Traditional wood plastic composites（WPC）is a kind of plastic composite materials, in which thermoplastic polymers (e.g. PE, PP, and PVC) and small molecule modified wood fibers are used as matrices and fillers, respectively. WPC has been widely used in the field of decoration because of its acceptable mechanical properties, wear-resisting, recyclability and other advantages. However, to the best of our knowledge, the commercially available wood fibers modified by small molecules such as stearic acid, maleic acid, organic silicone coupling agents etc. are compatible fillers instead of thermoplastic resins, due to the molecular chain grafted on the surface of the fiber is too short. Consequently, the content of the modified fiber in WPC is extremely limited, taking account of that mechanical properties of WPC will be drastically decreased with fiber content. Recently, to overcome the defects of traditional WPC, we have successfully designed and prepared a new composite materials entitled plasticizable biomass materials (PBM) by in situ reactive processing technique. PBM is mainly consist of large amount (70-100 wt.%) of thermoplastic macromolecule grafted biomass fibers (e.g. wood, straw, bamboo) and small amount (0-30 wt.%) of resins (e.g. PE, PP, PVC). After the in situ reactive processing modification, biomass fibers themselves can be thermoplastically extruded by usual extrusion without any addition of traditional plastics such as PE and PVC. The developed PBMs have the advantage of formaldehyde-free, none volatile organic compounds (VOC), high waste resource utilization etc., showing large potential application in the fields of indoor and outdoor decoration materials.