Building steel structure convenient to assemble

The utility model belongs to the technical field of building steel structures, and particularly relates to a building steel structure convenient to assemble, which comprises two steel plates, splicing grooves are arranged at two ends of the two steel plates, a splicing block is arranged in the two splicing grooves close to each other in a sliding manner, and disassembly and assembly components are arranged at four corners of the bottom end of each steel plate. The dismounting and mounting assembly comprises a U-shaped seat installed on one side of the bottom end of the steel plate, a beam column is arranged at the bottom of the U-shaped seat, one end of the U-shaped seat is rotationally connected with a large gear, a set of threaded holes are formed in the beam column, screws are in threaded connection with the interiors of the four threaded holes, a limiting groove is formed in the U-shaped seat, and a limiting block is arranged in the limiting groove. The splicing blocks slide in the two splicing grooves, s