Insulated sandwich panels for external walls, composed of autoclaved aerated concrete (ALC) panels as the base, combined with composite thermal insulation boards and 35mm thick Class A thermal insulation mortar, known as lightweight insulated sandwich panels for external walls, abbreviated as insulated sandwich panels. Insulated sandwich panels for external walls are divided into two types based on construction, Type 1 and Type 11. The system of prefabricated aerated concrete insulated sandwich panels consists of the insulated sandwich panels installed on the main structure, leveling layer of thermal insulation mortar, finishing layer, decorative layer, and thermal bridge insulation measures for beams, columns, and other components, known as the insulated sandwich panel system. It belongs to the integrated thermal insulation and structural product for prefabricated buildings.