Objective：To evaluate the clinical efficacy and safety of inetetamab-based therapy in patients with human epidermal growth factor receptor 2（HER2）positive metastatic breast cancer（MBC）. Methods：A retrospective analysis of the clinical data of 60 patients with HER2 positive MBC who received inetetamab-based therapy in Jiangsu Provin Hospital from July 2020 to December 2022 was conducted. The progression-free survival（PFS），overall survival（OS），objective response rate（ORR）and disease control rate （DCR）of patients treated with inetetamab therapy were analyzed. Results：A total of 60 patients with HER2 positive MBC over all lines of treatment with inetetamab were enrolled（one，n=9；two，n=14；three，n=13；four or higher，n=24），in cluding 24 cases of inetetamab combined with chemotherap 32 cases of inetetamab plus pyrotinib and chemotherapy，and 4 cases of inetetamab combined with other drug regimens. At the end of follow up，the median PFS of the 60 patients was 6.23 months. The median PFS of patients who received inetetamab-based therapy as a first-or second -line therapy was significantly longer than third or later line，12.27 vs. 5.63 months. Compared with treatment in combination with chemotherapy，combination with pyrotinib and chemotherapy provided a better PFS（7.73 vs. 4.60 months）. The ORR and DCR were 35.0% and 81.7%，respectively. The most common adverse events were anemia， leucopenia and neutrocytopenia. Conclusion：Inetetamab，especially in combination with pyrotinib and chemotherapy，has a significant efficacy and good safety in patients with HER2 positive MBC.