The invention relates to a stored liquid circulating cooling type torsion-increasing diamond wire with a polygonal cross section. The diamond line comprises a polygonal cylindrical steel wire body of a torsion structure and a plurality of diamond particles inlaid in the steel wire body. A plurality of spiral chip removal surfaces are formed on the steel wire body. A high manganese steel clad layer is arranged on the outer layer of the steel wire body. The edge of the steel wire body is provided with a plurality of embedding grooves and liquid inlets in a side-by-side mode, wherein the embedding grooves are used for embedding the diamond particles. Cooling liquid channels communicated with the liquid inlets and the embedding grooves are arranged in the steel wire body. The diamond particles are inlaid in the embedding grooves. The tops of the embedding grooves are provided with liquid storage cavities communicated with one another. The spiral chip removal surfaces are provided with liquid discharge ports communicated with the liquid storage cavities. The stored liquid circulating cooling type torsion-increasing diamond wire with the polygonal cross section is reasonable in structure, good in chip removal effect, capable of preventing chip accumulation, high in cutting efficiency, good in cooling effect and long in service life.