OBJECTIVE To evaluate the cost-utiliby of capivasertib combined with fulvestrant for the second-line treatment of hormone receptor-positive/human epidermal growth factor receptor-2-negative （HR+/HER2－） advanced breast cancer from the perspective of the Chinese healthcare system. METHODS A partitioned survival model was constructed using clinical data from the CAPItello-291 trial. Costs and quality-adjusted life years （QALYs） were used as the output indicators of the model， and the incremental cost-effectiveness ratio （ICER） was used as the evaluation indicator of the model. Using three times the per capita gross domestic product （GDP） of China in 2024 as the willingness-to-pay threshold （WTP）， this study analyzed the cost-utility of capivasertib combined with fulvestrant versus fulvestrant monotherapy in the treatment of HR+/HER2－ advanced breast cancer， and conducted sensitivity analysis and scenario analysis under conditions where the price of capivasertib was reduced by 50%， 60%， 70% and 95%， respectively. RESULTS The results of the basic analysis showed that compared with the fulvestrant monotherapy regimen， the ICER of capivasertib combined with fulvestrant was 843 038.46 yuan/QALY， which was higher than the WTP（287 247 yuan/QALY）. The one-way sensitivity analysis revealed that the top three factors with the most substantial influence on ICER were the utility value in the progression disease state， the price of capivasertib， and the utility value inthe progression free survival state. Probabilistic sensitivity analysis demonstrated the robustness of the basic analysis results. Scenario analysis revealed that even if the price of capivasertib were reduced by 95%， capivasertib combined with fulvestrant did not exhibit cost-effectiveness at the current WTP. CONCLUSION At a WTP of three times China’s GDP per capita in 2024， compared to fulvestrant monotherapy， capivasertib combined with fulvestrant as the second-line treatment for HR+/ HER2－ advanced breast cancer is not cost-effective.