High-strength composite board and preparation method thereof

The invention belongs to the field of preparation of composite boards, and discloses a high-strength composite board and a preparation method thereof. The high-strength composite board comprises an upper panel layer, a lower panel layer and a framework supporting layer located between the upper panel layer and the lower panel layer; the framework supporting layer comprises a first supporting framework and second supporting frameworks; the first supporting framework is of a latticed structure and comprises at least two layers of transverse supporting frames and a plurality of longitudinal supporting frames; each layer of transverse supporting frame is formed by arranging the multiple transverse supporting frames in parallel at intervals; the longitudinal supporting frames sequentially and longitudinally penetrate through each layer of transverse supporting frame upwards from the lower panel layer to the lower surface of the upper panel layer; the longitudinal supporting frames are evenly distributed at interva