In this paper, we have aimed to elucidate the therapeutic effect of intramedullary nailing (IMN) in treating comminuted proximal humeral fractures (CPHFs) and its influence on the recovery of shoulder joint function. For this purpose, 60 cases with CPHFs were selected, particularly from January 2020 to October 2021. In these cases, 28 cases were treated with a locking proximal humeral plate (LPHP) and assigned to the control (Con) group and the remaining 32 patients were treated with IMN and included in the research (Res) group. The therapeutic effect, surgical indicators, total complications, visual analogue scale (VAS) score, and postoperative shoulder joint function score were compared between the two arms. We observed that compared with the Con group, the effective rate in the Res group was higher while the operation time, intraoperative blood loss, and fracture healing time were shorter, the overall complication rate and VAS score were lower, and the postoperative shoulder joint function score was higher, all with statistical significance. The above results indicate that IMN is effective and safe in the treatment of CPHFs, which can validly reduce the discomfort of patients and facilitate the recovery of shoulder joint function.