The invention provides a high-performance environmental protection composite building material, which is prepared by the following steps: evenly mixing lime stone, biomass, PVC resin, ployethylene wax, stearic acid, stabilizing agent, low-temperature foaming agent and the like in proportion; and then carrying out the steps of rapid high temperature, shock chilling temperature reduction, die moulding, cold water soaking and vacuum dehumidification. Compared with single biomass composite building material, the product is more environment-friendly, the construction cost is lower and more superior, the service life is longer, and the processing excess materials can be fully recycled, thus being an ideal substitute of the single biomass composite building material.