AIM To explore the risk factors of drug-induced liver injury (DILI) of compound sulfamethoxazole (sulfamethoxazole-trimethoprim, SMZ-TMP) in acquired immunodeficiency syndrome (AIDS) patients and provide reference for clinical pharmacovigilance and rational drug use. METHODS The data of AIDS patients treated with SMZ-TMP in our hospital from December 2020 to December 2022 were collected retrospectively. The general information of patients with DILI after taking SMZ-TMP was compared with that of patients without DILI, and binary logistic regression equation was constructed to screen out the risk factors of DILI in AIDS patients induced by SMZ-TMP. RESULTS Totally 271 AIDS patients were involved, and 29 patients had DILI, all of whom were male. Among them, 27 patients were of hepatocellular injury pattern and 2 patients were of cholestatic injury pattern. All DILI patients were cured or improved after symptomatic treatment. Relevant factor analysis showed that, allergy history (OR=15.334，95%CI: 3.147 to 74.710), no receiving antiviral treatment or tenofovir+lamivudine+lopinavir/ritonavir (TDF+3TC+LPV/r) regimen (OR=56.123, 95% CI: 10.797 to 291.719), daily dose of SMZ-TMP ≥ 12 tablets (OR=52.809, 95% CI: 9.894 to 281.868), alanine transaminase (ALT) ≥ 23 U·L^-1 (OR=18.514, 95% CI: 3.993 to 85.843), CD4⁺ T cell ≤110·µL^-1 (OR=40.586，95%CI：6.625 to 248.634), and CD8⁺ T cell ≤ 920·µL^-1 (OR=135.978，95%CI：11.190 to 1 652.303) can increase the risk of SMZ-TMP related DILI in AIDS patients (P<0.05). CONCLUSION The incidence of SMZ-TMP related DILI is relatively high in AIDS patients. Allergy history, selection of antiviral treatment regimens, dose of SMZ-TMP, ALT level, and CD4⁺ and CD8⁺ T lymphocyte counts are the independent risk factors for SMZ-TMP related DILI in AIDS patients. Monitoring of high-risk population should be strengthened and early intervention measures should be taken.