A stator assembly of a hairpin winding motor, comprises a hairpin coil, which includes a first end including a pair of two ends of the hairpin coil arranged to be adjacent to each other in a radial direction, a second end including a pair of two ends of the hairpin coil arranged to be adjacent to each other outside the first end in the radial direction, and a third end including a pair of two ends of the hairpin coil arranged to be adjacent to each other outside the second end in the radial direction. Here, a plurality of such first to third ends are repetitively formed along a circumferential direction, and a fixing cap fixes a preset number of ends among the plurality of first to third ends repetitively formed along the circumferential direction.