The invention relates to a pipe fitting orifice trimming machine, belongs to the field of pipe fitting orifice trimming, and mainly solves the problems that a pipe orifice edge is manually beaten with a hammer to allow a pipe orifice to be circular, labor and financial resources are wasted and a workpiece surface is heavily damaged, and even the internal structure of a pipe fitting is affected in the prior art. The pipe fitting orifice trimming machine is characterized in that a power source is disposed on a fixing platform, the machine further comprises a pipe orifice trimming device and a plunger which is driven by the power source and moves linearly in a reciprocating manner, a clamp opening is formed in the pipe orifice trimming device, one side of the inner wall of the clamp opening is provided with an ejector header die in linkage with the plunger, and a workpiece groove for placing a workpiece is formed between the other side of the inner wall of the clamp opening and the ejector header die. By the arrangement, the pipe fitting orifice trimming machine has the advantages that when the workpiece is placed into the workpiece groove during use, the pipe fitting orifice can be efficiently and conveniently rounded through the ejector header die, labor and material resources are saved, and the internal structure of the pipe fitting is not damaged.