Urinary tract infection (UTI) is a common postoperative complication, so exploring its risk factors is helpful to provide a basis for clinical prevention. This study aims to analyse the risk factors for UTI after lumbar interbody fusion (LIF). A single-centre retrospective study was conducted on the clinical data of 358 patients treated with LIF from April 2020 to April 2023. In accordance with the results of postoperative urine culture, the patients were divided into UTI group (n = 19, those with UTI after LIF) and control group (n = 332, those without UTI after LIF). Binary logistic regression analysis was carried out through collecting the medical records of the two groups to probe into the risk factors for UTI after LIF. After seven patients were excluded, the remaining 351 patients were included in the analysis. In this study, 19 patients (5.41%) developed postoperative UTI, whereas 332 patients (94.59%) had no UTI. Regression analysis results showed drinking (odds ratio (OR) = 16.193, 95% confidence interval (CI): 1.017-257.860) and high preoperative C-reactive protein (CRP) level (OR = 3.237, 95% CI: 1.213-8.636) as risk factors for UTI after LIF. A high professional title of main surgeon (OR = 0.095, 95% CI: 0.010-0.932) and preoperative red blood cell (RBC) count (OR = 0.001, 95% CI: 0.000-0.198) were protective factors for UTI after LIF (p < 0.05). This study advocated strengthening the prevention and treatment of UTI in patients who had drinking history, high preoperative CRP level and low preoperative RBC count, and received LIF based on the study results. Attention should be paid to the training of physicians with low professional title.