Fabricated building steel structure with quick splicing structure

The invention relates to the technical field of building steel structures, in particular to a fabricated building steel structure with a quick splicing structure, which comprises upright column profile steel and a plurality of cross beam profile steel, the surface of the upright column profile steel is movably sleeved with a first fixed pipe and a second fixed pipe, and the top end of the second fixed pipe is welded with a profile steel placing piece; a plurality of first openings and a plurality of second openings are formed in the side face and the top of the profile steel containing piece correspondingly, and one ends of the multiple pieces of cross beam profile steel penetrate through the first openings correspondingly and are placed in the profile steel containing piece. According to the scheme, the profile steel placing piece is fixed to the surface of the stand column profile steel, when three or more pieces of cross beam profile steel are installed, only the multiple pieces of cross beam profile steel