Abstract: Human epidermal growth factor receptor (HER) 2 is overexpressed in approximately 15% of breast cancer patients and commonly associated with poor prognosis. The authors briefly describe the research progress of radionuclide-labeled molecular probes targeting HER2 in breast cancer imaging diagnosis and treatment. An overview of radionuclide-labeled monoclonal antibodies and antibody fragments, affinity bodies, nanobodies, and targeted peptides is presented, and it is summarized that radionuclide-labeled HER2 molecular imaging can noninvasively monitor the spatiotemporal heterogeneous expression and switching of HER2 status during disease progression and therapeutic response. The authors point out that, compared to conventional histopathological examination, radionuclide-labeled HER2 molecular imaging enables more efficacy evaluation assessment and also offers the potential possobolity for targeted breast cancer treatment.