The invention puts forward a welding mechanism for a pipe butt joint angle welding. The welding mechanism comprises a support, wherein a rotating mechanism is horizontally arranged on the support, a left core shaft is inserted into the rotating mechanism, one end of a right core shaft is connected with the left core shaft, the other end of the right core shaft tilts upwards, and both the left coreshaft and the right core shaft are provided with external threads; the rotating mechanism is provided with an air source inlet, the left core shaft is provided with an air source channel I communicating with the air source inlet, and the right core shaft is provided with an air source channel II enabling the air source channel I to communicate with the outside world. The right core shaft is obliquely connected with the left core shaft, a taper sleeve II is inserted into a spring sleeve II to fix a pipe fitting, a taper sleeve I is inserted into a spring sleeve I to fix another pipe fitting, after pipe butt joint angle welding is realized, a finished product will not have a large location degree tolerance, because the fixing effect is good, a workpiece does not need to be corrected by flames or an external mechanical force method, and the welding quality is guaranteed.