Waterproof construction hanging formwork and waterproof construction method

The invention provides a waterproof construction hanging formwork and a waterproof construction method. The waterproof construction hanging formwork comprises an upper formwork assembly and a lower formwork assembly, the upper formwork assembly comprises a left upper half formwork, a right upper half formwork and a half formwork connecting piece for connecting the two half formworks, the left upper half formwork and the right upper half formwork are bilaterally symmetrical half pipe bodies, and a plurality of positioning plates are arranged on the inner walls of the upper ends of the half pipe bodies; an arc-shaped bulge is arranged on the inner wall of the pipe body below the positioning plate, and the edge of the lower end of the half pipe body is turned outwards; the lower formwork assembly comprises a left supporting plate, a right supporting plate and a supporting plate connecting piece connecting the two supporting plates, the left supporting plate and the right supporting plate are in butt joint and sp