The invention provides an assembling type building outer heat-preserving wall used for being installed on a building. The assembling type building outer heat-preserving wall comprises an inner clamping core plate and an outer clamping core plate which are arranged side by side. A cavity is formed between the inner clamping core plate and the outer clamping core plate. The assembling type building outer heat-preserving wall further comprises a connecting part arranged in the cavity, and a pipeline located in the cavity, wherein the connecting part can be matched with the building. The inner clamping core plate comprises two layers of first steel plates and a first heat-preserving layer sandwiched between the two layers of first steel plates. The outer clamping core plate comprises two layers of second steel plates and a second heat-preserving layer sandwiched between the two layers of second steel plates. The heat-preserving wall plays an actual important role in power transformation, construction speed is high, sand wind is effectively prevented, the problem that cables and the like are exposed out of the ground outside the wall is solved, and the wall is simple in structure, good in actual application effect and high in practical value.