Wood is a green, environmentally sustainable, high-performance structural material that is an attractive candidate to replace nonenvironmental structural materials. However, the mechanical performance of natural wood is generally insufficient in many advanced engineering structures and applications. Herein, we report a simple and effective strategy in a new type of green-enhanced wood development to synthesize a high mechanical biomass structure material from renewable wood resources. In this process, the lignin of the natural wood is partially removed, and the hard cell walls become pliable and easy to handle. After treatment, the wood fiber structure is preserved, and the wood fibers are closely arranged after densification, which shows the reinforced wood with high mechanical properties. The resulting reinforced wood is 8 times stronger than the starting wood and comparable to widely used structure materials such as concrete, stainless steel, aluminum alloy, and magnesium alloy. This method of manufacturing reinforced wood with green, rich, and renewable natural wood is extremely attractive for the sustainable development of engineering structural materials, which broadens the potential of wood as structural materials.