Building steel structure supporting beam

The invention discloses a building steel structure supporting beam. The building steel structure supporting beam comprises a main beam body, a sharp supporting assembly, an extending-out beam assemblyand a cement embedded part, wherein the main beam body comprises a main beam, a trapezoidal convex strip, an extending-out beam slot, a circular blocking piece, a side seat plate, a bottom slot, a double-thread screw, middle seat plates and a swirl hexagonal prism; the upper end of the main beam is equipped with the trapezoidal convex strip; the extending-out beam slot which is through left and right is formed in the main beam; the lower end of the main beam is equipped with the bottom slot; the middle position of the double-thread screw is fixedly connected with the swirl hexagonal prism; the left end of the double-thread screw is equipped with a positive thread; the right end of the double-thread screw is equipped with a negative thread; the middle position of the lower end of the mainbeam is fixedly connected