The utility model discloses an exterior wall body structure built of decorative heat-insulating compound building blocks. The exterior wall body structure is a heat-insulating compound building block; the heat-insulating compound building block comprises a light architectural concrete basal body and heat-insulating core materials are tightly connected in a dovetail-type zero-clearance manner; a decorative surface is adhered to the outer layer surface of the building block, and a mortar joint polyphenyl foam plastic heat-insulating hold-down strip is placed on the building block in the position of the heat-insulating core materials; the building block is connected with a main wall into a whole by adopting sand pulp cohesion and truss type or framework type bar reinforcement binding steel bar. The light architectural concrete basal body has good impermeability, the outer layer surface can be made into various decorative surfaces in such manners as molding, splitting, scabbling and the like; the mortar joint polyphenyl foam plastic heat-insulating hold-down strip placed in the position of the heat-insulating core materials can block the 'heat bridge' of masonry joints, the building block is connected with the main wall into a whole by adopting sand pulp cohesion and truss type or framework type bar reinforcement binding steel bar, so as to form a high-performance compound exterior wall body structure which is provided with the same service life with the structure of a main building and integrates the functions of decoration, heat insulation and enclosure as a whole, thereby solving the technical problems that the a decorative surface for conventional exterior wall exterior insulation system is required to made at the later period, the construction procedure is complex, and the service durability is poor.