The invention provides a sandwich board with a sine-cosine continuous beam structure and orthogonally arranged cores and a preparation method of the sandwich board. A wire cutting technology is applied to metal plates of different thicknesses to obtain square-section metal wires conforming to a sine or cosine law, thereby obtaining sine or cosine core single bodies; the sine core single bodies andthe cosine core single bodies are arranged in an orthogonal manner and welded to an upper surface metal board and a lower surface metal board to obtain the sandwich board with the sine-cosine continuous beam structure and the orthogonally arranged cores. According to the method, the traditional sandwich board pyramid type or honeycomb lattice structure is replaced by introducing the sine cores and the cosine cores, thereby avoiding the structural flexion of a bar in the traditional bar structure; in addition, a shock wave reaching a sine or cosine peak or trough is dispersed along a metal wire, so that the stress concentration at the contact between a surface board and a core is weakened, and the shock absorption effect is enhanced.