Objective: To explore the influence of distal humeral settlement and shoulder joint function of locking plate in the treatment of proximal humeral fracture using the medial support fixation. Methods: Retrospectively analysed 78 proximal humeral fracture patients who underwent locking plate treatment in our hospital from April 2012 to January 2015, 72 cases with complete patient data, which included 39 cases with the medial support fixation (group A) and 33 cases without medial support fixation (group B). The humeral distal subsidence degree and shoulder joint Neer scores were compared between the two groups of patients post operation for 3, 6 and 12 months. We also recorded postoperative complications to compare the clinical effect of two groups of patients. Results: Humeral distal subsidence degree of group A were less than that of group B (P<0.05) in postoperative 3, 6 and 12 months. There was no statistical significance in the humeral distal subsidence degree of D1, D2 and D3 of group A after operation for 3, 6 and 12 months (P>0.05). D1, D2 and D3, the humeral distal subsidence degree of group B, had statistically significant differences (P<0.05), postoperation Neer scores in patients of group A were higher than in group B for 3 months, 6 months and 12 months, the difference was statistically significant (P<0.05).The differences of total complications between two groups has no statistical significance (P>0.05). Conclusion: The application of locking plate proximal humeral fractures using the medial support fixation helps strengthen the stability of the shoulder joint, reduces postoperative settlement of distal humerus, and promotes the recovery of shoulder joint function.