Low-energy-consumption energy-saving heat-preservation multi-story building structure and construction method

The building structure comprises an outer wall heat preservation enclosure structure formed by splicing a plurality of outer wall panels, heat preservation layers are arranged in the outer wall panels, and the heat preservation layers in all the outer wall panels on the same layer abut against one another to form a continuous heat preservation structure. The thermal insulation layers of the upper and lower external wall panels abut against each other or are in lap joint to form a continuous thermal insulation structure; the left ends, the right ends and the bottom ends of the external wall panels are bent and extend towards the outer sides of wall bodies of the external wall panels to form bent protruding parts, every two adjacent external wall panels on the same layer are spliced in a linear shape or an L shape, the annular steel bars of the two external wall panels at the splicing position are not located on the same horizontal plane, and after splicing, the bent protruding parts of the two external wall pa