The invention relates to a constructional material, in particular to a heat preservation and decoration board for a building exterior wall. The invention has a structure that the board mainly comprises three layers; an inner layer serves as an insulating course, an outer layer serves as a decorative layer and a middle layer serves as a binding course; wherein, the insulating course has a polyphenyl board or a plastic extrusion plate or a polyurethane board; the decorative board has various exterior wall facing dopes or a decorative plate; the binding course is the polymer caking agent layer, the insulating course and the decorative layer are stuck into a whole by the cementing action of the polymer caking agent. The invention has convenient construction, easy manipulation, low cost, good heat prevention effect and strong suitability, thereby contributing to the quick popularization of energy consumption of a building.