The invention discloses a power gain type solar backboard material. The backboard material is composed of a gain layer, a base body layer and a weather-proof layer. The obtained backboard material has the good visible light reflectance, and meanwhile has the good water vapor barrier property, mechanical performance, dimensional stability and long-term weather resistance. The preparation technology is simple, convenient and stable in product performance, can have obvious gain for electricity generation power of a solar assembly, can effectively decrease the cost per kw h of a solar power station, can meet the requirement of long-term insulativity and weather resistance of the solar assembly in power station systems of different scales, and is excellent in comprehensive performance.