The utility model relates to an assembled outer wall system, steel construction assembled outer wall system outside -in includes outer architectural surface, vacuum insulation panels layer, basal plate, fossil fragments, filling layer and wall inner panel in proper order, and on outer architectural surface was fixed in the basal plate, the vacuum insulation panels layer set up between outer architectural surface and basal plate, and basal plate and wall inner panel are fixed in the fossil fragments both sides respectively, by basal plate and wall inner panel surround formation, by being provided with the filling layer in the fossil fragments divided cavity, the filling layer is non - pouring type stopping. The utility model discloses a component that the complete set was used can effectivefixed basal plate and vacuum insulation panels or STP heat decorative integration plate. And be mechanical connection between each layer, do not have the hidden danger that drops, can improve the security, also can conveniently replace when damaging.