The invention provides a novel prefabricated thin type heat preservation composite outer wall and a structural system and construction method thereof.The novel prefabricated thin type heat preservation composite outer wall comprises a panel, a heat preservation layer, steel wire mesh pieces, novel self-compacting concrete and a novel wallboard tensile flexible connector; one or more positions, in a sandwich composite wallboard, of the heat preservation layer are broken and arranged in a discontinuous mode; the novel self-compacting concrete is poured into a cavity formed between the panel and the heat preservation layer and wraps the steel wire mesh pieces on the two sides respectively; meanwhile, the concrete is integrally poured at the discontinuous arrangement areas.The position between the corresponding discontinuous arrangement area and a horizontal structural component of the heat preservation layer is filled with a supplementary heat preservation material to prevent a hot and cold bridge.The outer wall is conducted and assembled with the horizontal structural component through a connection assembly.The novel prefabricated thin type heat preservation composite outer wall is light and thin in wallboard, easy to transport and install, does not need a keel and is directly assembled to the horizontal structural component, cost brought by the keel is lowered, the construction procedure is simplified, and the novel prefabricated thin type heat preservation composite outer wall can be widely applied to civil concrete and steel structure buildings.