Few reports have been conducted to comparing surgical results and safety evaluations between the different types of infections in geriatric patients with thoracolumbar infections. The aim of this study is to investigate the safety and efficacy of surgical treatment for thoracolumbar infections in elderly patients. 21 patients with pyogenic spondylodiscitis (PS) and 26 patients with tuberculous spondylodiscitis (TS) were enrolled in the study. All patients were treated using one-stage posterior debridement, decompression, and pedicle screw fixation. Comparison of operative safety parameters between the two groups. Clinical efficacy was evaluated using visual analogue scale (VAS) score, the American Spinal Injury Association (ASIA) grade, the short form (SF)-36 survey and Oswestry disability index (ODI) to determine patient quality of life pre- and post-operatively. Hospitalisation and intensive care unit duration in the PS group were significantly shorter than in the TS group (P < 0.05). The total incidence of post-operative complications for both groups was 44.7%. More complications occurred in the TS group, but the difference was not significant. The scores of VAS, ODI and SF-36 of all 47 patients were significantly improved compared with those before operation.The VAS and SF-36 scores (physical component) were significantly better in the PS group 6 months post-operatively, and the SF-36 (mental component) scores were significantly better in the PS group at the 1-year follow-up. Neurological status in both groups improved post-operatively, and 83% of patients reported satisfactory results based on the modified MacNab standard. Imaging results showed that bone graft fusion improved in both groups at 6 months, 1 year and at the final follow-up. One-stage posterior debridement, decompression, interbody fusion, and internal fixation can be considered a safe and effective method of treating spinal infections in the elderly. This method can improve nerve function, reconstruct spinal stability, and enhance the quality of life of elderly patients. Both PS and TS who underwent surgery achieve similar clinical and radiological results.