Clamp for building heating and ventilation pipe welding

The utility model discloses a building heating and ventilation pipe welding clamp which comprises a workbench, supports are fixedly connected to the upper sides of the left end and the right end of the upper side wall of the workbench, first clamping seats are fixedly connected to the upper ends of the two supports, and second clamping seats are arranged at the upper ends of the two first clampingseats. And fixing mechanisms are arranged in the middles of the upper ends of the two sets of second clamping seats correspondingly, each fixing mechanism comprises a screw hole and a clamping block,and a screw rod is spirally connected to the upper end of each screw hole. The fixing mechanisms are arranged in the middles of the upper ends of the two sets of second clamping seats at the upper end of the workbench, the clamping blocks in the fixing mechanisms are arc-shaped and are attached to the outer side wall of the building heating and ventilation pipe, and the clamping blocks and the building heating and ventila