OBJECTIVE To evaluate the cost-utility of disitamab vedotin （DV） combined with toripalimab versus platinum-containing chemotherapy as first-line therapy for locally advanced or metastatic urothelial carcinoma（UC） with human epidermal growth factor receptor 2 （HER2） expression from the perspective of China’s health-care system.METHODS A cost-utility analysis was performed. A three-state partitioned survival model was constructed based on the RC48-C016 trial with a 1-week cycle length. The long-term health benefits [quality-adjusted life years（QALYs）] and costs of disitamab vedotin combined with toripalimab versus platinum-containing chemotherapy as first-line therapy for locally advanced or metastatic UC with HER2 expression were simulated. The simulation time horizon was set to 15 years， and the discount rate was 4.5%. The willingness-to-pay （WTP） threshold was defined as twice China’s per capita gross domestic product（GDP） in 2025 （199 330 yuan/QALY）. The incremental cost-effectiveness ratio （ICER） between the two groups was compared， and one-way sensitivity analysis and probabilistic sensitivity analysis were conducted.RESULTS Compared with platinum-containing chemotherapy regimen， the DV plus toripalimab regimen yielded an additional 1.01 QALYs with an incremental cost of 183 224.45 yuan， and the ICER was 181 728.15 yuan/QALY， which was below the WTP threshold. At the current threshold， the probability that the DV combination regimen had a cost-utility advantage was 79.9%.CONCLUSIONS Taking twice China’s per capita GDP in 2025 as the WTP threshold， DV combined with toripalimab exhibits a cost-utility advantage over platinum-containing chemotherapy as first-line treatment for HER2-expressing locally advanced or metastatic urothelial carcinoma.