The invention provides a steel framework of a switch cabinet. The steel framework includes stand columns, side cross beams, small stand columns and large cross beams, the stand columns are fixedly connected with the side cross beams and the large cross beams, the side cross beams are mutually parallel, the large cross beams are mutually parallel, the side cross beams and the large cross beams are mutually perpendicular in direction, and the small stand columns are fixedly connected to the side cross beams located at the upper part; and the steel framework also includes corner fastening devices, the corner fastening devices fixedly connect the stand columns, the side cross beams and the large cross beams through fasteners, the stand columns are made of rectangular closed sectional materials, and sealing parts of the closed sectional materials are provided with collision reinforcing rib devices. According to steel framework of the switch cabinet, the closed rectangular steel sectional materials are obtained by rolling through a plurality of processes, the mechanical stability is good, the torsion resistance is high, and the steel framework can bear strong impact force generated by a 80KA short circuit current alone.