Building steel structure welding equipment

The invention belongs to the technical field of steel structure welding, and discloses building steel structure welding equipment which comprises a lifting mechanism used for supporting structures such as a steel structure and adjusting the height of the structures; the extension mechanism is used for expanding the supportable area of the lifting mechanism; the multiple fixing assemblies are arranged at the top of the extending mechanism and used for fixing the steel structure; the number of the welding pieces is at least one, and the welding pieces are arranged above the extending mechanism. Through cooperation of the fixing assemblies and the extending mechanisms, the steel structures with different sizes can be fixed on the basis of supporting the steel structures, multiple areas of the steel structures can be fixed, the multiple steel structures can be fixed at the same time, and the multiple areas of the multiple steel structures can be fixed at the same time; and instability of one or more steel structu