Objective To evaluate the direct economic burden caused by surgical site infection(SSI)in patients with orthopaedic trauma under the payment management of disease diagnosis-related groups (DRG). Methods Clinical data of patients with orthopaedic trauma in a tertiary first-class hospital from May 1, 2022 to May 30, 2023 were surveyed retrospectively. Patients were grouped based on whether SSI occurred. Differences in average length of hospital stay, average hospitalization expense, and other indicators between SSI patients and non-SSI patients in the same DRG subgroup were compared, and the direct economic burden caused by SSI was analyzed. Results A total of 435 patients who paid according to the DRG payment management were included in the study. Twenty-two patients had SSI, with an SSI incidence of 5.06%. Both the average length of hospital stay and average hospitalization expense of patients in the SSI group were higher than those in the non-SSI group, with statistically significant differences (P < 0.05). The DRG subgroups of SSI patients were mainly four groups: IF45, IF15, IJ13, and ZC13. Among them, the average length of hospital stay of SSI patients in the IF45, IF15, and ZC13 groups increased significantly (P < 0.05), and the average hospitalization expense of SSI patients in the IJ13 group increased significantly (P < 0.05). Conclusion Under the DRG payment management, the direct economic burden of orthopaedic trauma patients with SSI increases significantly. It is necessary to periodically evaluate and identify high-risk DRG subgroup patients, so as to adopt precise infection control interventions and reduce SSI incidence.