Abstract: With water-soluble phenol-formaldehyde resin as intermediate, Cunninghamia lanceolata wood-montmorillonite nanocomposite(WMNC) was prepared through vacuum impregnation and characterized with XRD, SEM, FTIR and TG-DTA analyses respectively.XRD analysis indicated that wood crystallinity of WMNC decreased, MMT exfoliates and some nano silicate layers entered into the non-crystallized microfibrillar region of wood cell wall.Wood structure and its impregnation are both anisotropic.Due to the nonuniformity of MMT organic modification, PF intercalation as well as wood impregnation, MMT configuration and distribution in wood are diverse.SEM graphs of WMNC show that some silicate grains block in wood cell lumen, some silicate layers adhere to the inner surface of wood cell wall, and some exfoliated MMT layers even penetrate into wood cell wall.The concluded hydroxyl bonding of WMNC increases and its ether bonding decreases.It is considered that MMT and wood interact with certain hydrogen binding and chemical linking.Compared with wood and PF-impreg, the pyrolysis process of WMNC changes;the starting decomposing temperature decreases and the pyrolysis weight loss at high temperature decreases greatly.WMNC indicates some nanoeffect of inorganic MMT nanolamellae.