Heat-insulating and waterproof coating composition for building external wall and application method of heat-insulating and waterproof coating composition

The invention discloses a heat-insulating waterproof coating composition for a building external wall and an application method thereof. The composition comprises a primer layer and a finish paint layer, the primer layer is of a micropore structure and has viscosity, and the primer layer and the finish paint layer are bonded together. According to the invention, polyacrylic acid, starch, a surfactant and a tackifier are utilized to prepare the viscous primer layer with a microporous structure, so that the primer layer can be conveniently bonded with the finishing coat layer in the later period, a bonding layer does not need to be prepared, and the process is shortened. Besides, the acrylate emulsion is used as a film-forming substance, the hollow glass beads, the zirconia ceramic powder, the ytterbium-modified nano aluminum oxide powder and the rare earth are utilized to play a role in blocking heat conduction, and the four components cooperate with each other, so that the heat insulation performance of the p