In this case, we reported that margetuximab plus chemotherapy was effective as later-line therapy in a postmenopausal Chinese woman with metastatic diseases, who was diagnosed with estrogen receptor -, progesterone receptor (PR)-, HER2+ invasive ductal carcinoma...she received margetuximab plus capecitabine as the third-line treatment, the metastatic lesions in the liver were obviously shrunk, indicating clinical partial response and the PFS was 7 months. This case revealed that margetuximab plus chemotherapy may be an appropriate option for the patients who progressed after treating with anti-HER2 monoclonal antibodies and pyrotinib.