Building outer wall heat insulation flame-retardant belt and construction method thereof

The invention relates to a building outer wall heat insulation flame-retardant belt and a construction method thereof. The wall of the base layer is sequentially provided with an adhesive layer, a fireproof isolation layer, an alkali-resistant fiberglass gridding cloth and a surface mortar layer from inside to outside, wherein the adhesive layer is made of POLYMENT120 polymer modified cement mortar, the thickness of the adhesive layer is 1 to 1.5 millimeters, and the fireproof isolation layer is made of POLYMENT710 expanded vitrified micro-bubble thermal insulation mortar. Because the expanded vitrified micro-bubble thermal insulation mortar has high fireproof level, simple construction process, low cost investment, thermal insulation property, non-burnable property and non-propagation property, and when the fireproof isolation belt (flame-retardant belt) is applied to the positions such as the floor of each layer of a building, the upper edge of a window and the like, the integral fireproof performance of an outer thermal insulation system of a building outer wall is improved. The used expanded vitrified micro-bubble thermal insulation mortar has high fireproof level.