Abstract: In the context of precision medicine, although individual treatment of breast cancer under the guidance of molecular classification has become the norm, a precision treatment program with increased efficiency and quality is still required. Compared with the traditional real-time fluorescent quantitative polymerase chain reaction (PCR), the droplet digital PCR (ddPCR) has obvious advantages in the detection of rare mutations and copy number variations, as well as the integration with the second-generation-sequencing technology. This paper reviews the application of a ddPCR platform in different breast cancer subtypes and explores new horizons of breast cancer research through the ddPCR technology.