The invention belongs to the technical field of composite materials, and relates to a composite laminate and a preparation method thereof. The composite laminate comprises an upper surface layer, a core layer and a lower surface layer from top to bottom sequentially, and the upper surface and the lower surface of the core layer are connected with the upper surface layer and the lower surface layer respectively. The continuous fiber enhanced thermoplastic composite board has wider application space, corrosion of sunlight, rain water and the like to the inside of the continuous fiber enhanced thermoplastic composite board is prevented, and the ageing resistance of the composite material is enhanced.