Abstract: OBJECTIVE To analyze the changing trend of structure of hospitalization costs of the AIDS patients and observe the influencing factors. METHODS By means of retrospective study， the changes of hospitalization costs per case and their compositions of 771 AIDS patients who were hospitalized in Beijing Ditan Hospital Affiliated to Capital Medical University from 2019 to 2024 were analyzed. Univariate analysis and multiple linear regression analysis were performed to explore the influencing factors for the hospitalization costs. RESULTS The total hospitalization cost per case of the hospitalized patients with AIDS showed a downward trend， decreasing from 27 044.03 yuan in 2020 to 9 329.80 yuan in 2024. The structure of the cost has been continuously optimized， with the proportion of pharmaceutical expenses decreasing by 7.94%， the proportion of consumable expenses decreasing by 2.04%， while the cost of diagnosis and treatment remained the core component. The analysis of structural variation indicated that the proportions of diagnosis and treatment fees as well as pharmaceutical expenses fluctuated significantly， while the proportions of blood and blood products expenses as well as consumables expenses continuously decreased (all P＜0.05). Multiple linear regression analysis showed that the length of hospital stay(β=0.383)， number of additional diagnoses (no less than 6: β=0.585)， patient origin (out-of-town: β=0.306)， type of medical insurance (resident-based medical insurance: β=0.115)， and surgical status (β=0.054) were the influencing factors for the hospitalization costs(all P＜0.05). CONCLUSIONS The hospitalization costs of the hospitalized patients with AIDS have been remarkably controlled in the hospital. The length of hospital stay and number of additional diagnoses are the major clinical factors affecting the costs. It is necessary to pay close attention to the economic burden of the out-of-town patients and the resident-based medical insurance patients.