The invention discloses an outdoor high wear resistant PVC plastic-wood composite board for buildings. The composite board is made of the following components by weight: 80-90 parts of PVC, 60-79 parts of rice straw powder, 20-25 parts of PS, 5-8 parts of trimethylolpropane triacrylate, 3-7 parts of sorbitol, 6-11 parts of phenol, 2-5 parts of formaldehyde, 4-8 parts of caustic soda, 5-9 parts of an acrylonitrile-butadiene styrene copolymer, 4-8 parts of calcium stearate, 2-5 parts of methylethylketoxime, and 4-8 parts of molybdenum dithiocarbamate. The outdoor high wear resistant PVC plastic-wood composite board provided by the invention ahs the advantages of high strength, good plasticity, wear resistance, low cost, strong corrosion resistance and the like, is encironment-friendly, and can be widely used in building decoration, door and window frames, furniture manufacturing and other fields.