Background The incidence of gynecological diseases in China is rising year by year, with high hospitalization costs and a large economic burden on patients.Objective To analyze structural changes in hospitalization costs and identify key cost drivers for gynecological patients, thereby providing evidence-based strategies for hospitals to optimize expenditure management and alleviate financial burdens during inpatient care.Methods Structural change degree and gray correlation analysis were used to quantitatively analyze the structural changes and correlation degree of gynecology patients' hospitalization costs from 2020 to 2023 in a tertiary maternal and child health care specialty hospital in Jiangsu, China.Results From 2020 to 2023, the degree of structural change in hospitalization costs for 37 149 patients was 25.14%, with the highest degree of variation occurring from 2022 to 2023 (13.62%). This was mainly driven by the increase in diagnosis fees and consumable costs, and the decrease in surgical fees and drug costs. The top two contributors to structural change were drug costs and diagnostic costs, with a cumulative structural change contribution exceeds 55%. The rates of nursing fees and medical service fees were low. The top two correlation coefficients were medical service fees and diagnostic fees. After the implementation of diagnosis related groups (DRG) payment reform, the average hospitalization cost per patient decreased significantly.Conclusion The declining pharmaceutical expenditures coupled with rising diagnostic and medical supply costs have led to structural cost imbalances, while the implementation of DRG payment reform has reduced per-case hospitalization expenses. Establishing a dynamic monitoring mechanism becomes imperative to facilitate price adjustments and implement refined cost-control measures, thereby promoting rational allocation of medical resources.