As a typical anisotropic material, wood exhibits significant volume expansion/contraction during adsorption/desorption of water, increasing the risk of mold infection and cracking. Herein, we have designed a plexiglass coating on the surface of wood to overcome this shortcoming. Based on the high light transmittance of the acrylic glass, the as-prepared composite material retains the original texture and color of wood. Ethanol solvent enhances the wettability of methyl methacrylate (MMA) with wood, so that acrylic glass can grow in situ in shallow pores on the surface of wood. The design enhances the interface contact between the plexiglass coating and wood. Further relying on the super-hydrophobic properties of stearic acid (SA), the composite wood exhibits long-lasting mildew and cracking resistance. The excellent comprehensive performance of composite wood has great application potential in the field of structure and decoration.