The novel composite building material board comprises a front precastbamboo cement layer, a rear precast bamboo cement layer and a sandwich layer, wherein the interior of each of the precast bamboocement layers is poured by bamboo and cement blocks, which are built to be shaped like a Chinese character 'feng'; the sandwich layer is a wood keel space formed by wood keel, and the wood keel space is filled with lightweight aggregate concrete, such as adhesive polystyrene granule insulating mortar and ceramsite, and thermal insulation materials, such as foamed concrete. As bamboo and cementare arranged in the precast bamboo cement layers of the building material board, traditional steel bars are effectively replaced; as thebamboo has extremely small shrinkage and extremely strong elasticity and ductility, and are easily accessible and short in growth cycle, and the sandwich layer is made of a light material and has the performance of heat insulation, heat preservation, sound insulation and fire resistance, the building material board is large in density, high in strength, strong in water resistance and seepage resistance, good in thermal insulation, simple and quick in manufacture process and low in general cost and price, and saves manpower, and accordingly, the cost of the building material is greatly lowered.