The invention relates to the technical field of building, and provides an efficient construction method of a decorative composite wall. The efficient construction method of the decorative composite wall comprises the following steps that a prefabricated insulating board is adhered to the wall face of a foundation wall, the insulation board comprises a main insulating layer and an insulating surface layer, and the main insulating layer is adhered to the wall face of the foundation wall; a fixed piece passes through the insulating board so that the insulation board is further fixed on the foundation wall; the preparation material of the main insulating layer is insulating mortar; the insulating mortar comprises mixed powder, vitrified micro-bubbles, and water; the mixed powder comprises rubber powder, cement, clay, and polypropylene fiber; the preparation material of insulating surface layer is insulating wall coating; the insulating wall coating comprises water, ash calcium, coarse whiting, metal powder and coating resin; and the efficient construction method is short in construction period and the construction process is simple. The invention also provides the decorative compositewall prepared by the efficient construction method, and the wall is short in construction period and good in heat preservation.