TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The component A is copolymer E of ethylene and at least one monomer C, or a blend F of ethylene and at least two monomers C, which are mixed. The monomer C is 1-6C alkyl acrylate, 1-6C alkyl methacrylate, ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic acid anhydride. The copolymer E with at least one monomer C is acrylic acid or methacrylic acid. The blend F with at least one monomer C is an acrylic or methacrylic acid. The component B is copolymer M of ethylene and at least one monomer D, or blend N of ethylene and at least two monomers D, which are mixed; The monomer D is glycidyl acrylate, glycidyl methacrylate, 1-6C alkyl acrylate or 1-6C alkyl methacrylate. The copolymer M with at least one monomer D is glycidyl acrylate or glycidyl methacrylate, and the blend N with at least one monomer D is glycidyl acrylate or glycidyl methacrylate. The connection layer comprises component A comprising carboxylic acid group, and component B comprising epoxy group, which are mixed in equimolar ratio. The thickness ratio of the weathering layer, connection layer, structural reinforcement layer and the reflective layer is 4-40:10-50:40-400:20-150. The modified polypropylene is prepared by: mixing and modifying polypropylene with a heat stabilizer; grafting, mixing and modifying polypropylene with the heat stabilizer; mixing polypropylene, inorganic filler and heat stabilizer, where engineering plastic is a polyamide, or combination of polyphenylene ether and polystyrene. The weathering layer is fluorine material alloy layer of fluorine layer or inorganic modified material, and the fluorine material alloy layer is prepared by modifying the inorganic modified material. The fluorine material is polyvinyl fluoride, polyvinylidene fluoride, ethylene-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride, or vinyl fluoride and vinyl ether copolymer. The inorganic material is metal compound of formula (JxAy). The reflective layer is an alloy layer of polyethylene, polyethylene, segment containing ethylene (-CH2-CH2-) copolymers, UV-stabilizer and modified inorganic white pigment blend.J = Si, Mg, Ti, Zn, Al, Mo or Ba;A = O, S or SO4; andx, y = 1-3.Preferred Method: The preparation method further comprises pelletizing the connecting material layer, structural reinforcing layer material and the reflective layer respectively by the extruder to obtain connecting layer plastic particles, plastic particles of structural reinforcement layer, and plastic particles of reflective layer, and (ii) subjecting obtained particles to melt coextrusion using an extruder, and then coating the obtained particles on the weathering layer.