OBJECTIVE To evaluate the cost-effectiveness of pyrotinib combined with capecitabine in the second-line treatment of human epidermal growth factor receptor- 2（HER-2）positive advanced breast cancer from the point of view of medical and health system ，and to provide reference for the selection of clinical therapy plan and national health decision. METHODS The dynamic Markov model was constructed on the basis of a multicenter ，open，randomized controlled phase Ⅲ clinical trial in 29 centers in China. The simulation time limit was 8 years，and the cycle was 21 days. The cost-effectiveness of pyrotinib combined with capecitabine （observation group ）were compared with that of lapatinib combined with capecitabine （control group ）in the second-line treatment of HER- 2 positive advanced breast cancer. The incremental cost-utility ratio （ICER）was calculated by using quality-adjusted life year （QALY）as output indicators ，and the sensitivity analysis was carried out to validate the robustness of the results of basic analysis. RESULTS The results of basic analysis showed that compared with control group ，the incremental cost per capita and incremental utility per capita of observation group were 67 953.82 yuan and 0.40 QALYs；ICER was 168 861.89 yuan/QALY，which was lower than the willing to pay （WTP）threshold（217 500 yuan/QALY）represented by 3 times of China ’s per capita GDP in 2020，indicating the treatment plan of the observation group is more cost-effective. The results of single factor sensitivity analysis showed that the proportion of patients treated with trastuzumab or pyrotinib after entering disease progression （PD）status in the control group ，the proportion of patients treated with lapatinib or trastuzumab after entering PD status in the observation group ，the cost of capecitabine and other parameters showed great impact on ICER ，but those parameters didn ’t cause the reverse of basis analysis results. The results of probabilistic sensitivity analysis showed that when the WTP threshold was 217 500 yuan/QALY，the probability that the treatment plan in the observation group was cost-effective was 94.10％. The results of partition survival model analysis were consistent with those of dynamic Markov model. CONCLUSIONS On the premise of taking 3 times of China ’s per capita GDP in 2020 as the WTP lin- threshold， the second-line treatment of HER- 2 positive wang9805@163.com advanced breast cancer with pyrotinib combined with capecitabine is more cost-effective than that with lapatinib combined with capecitabine.