The invention relates to an exterior wall waterproofing heat-insulating decorating integrated material and a preparation method thereof.The preparation method includes: using conventional resin like polyurea and polyurethane as raw materials, adding compound micropowder prepared from solid waste and sludge, and adding a mixed modifier and a thixotropic agent to prepare A-compound slurry; adding a promoter and a hardener, and performing spray coating, brush coating, roll coating and pouring methods to obtain the exterior wall waterproofing heat-insulating decorating integrated material.The material has the comprehensive advantages of good waterproof effect, high heat insulativity, high hardness, high hole closing rate, low density, good anti-seepage performance, high corrosion resistance, low linear expansion coefficient, high softening temperature, oxidization resistance, aging resistance, flame retardancy and firmness in binding with a substrate.When the material is used for building exterior walls, multiple times of leveling, waterproofing, heat insulating and decorating construction are not needed, on-site moisture-free operation and one-time forming can be realized, and the material is short in construction period, extremely low in cost and great in market prospect.