BackgroundAnnually, approximately 1.7 million women are diagnosed with breast cancer worldwide. Engaging in regular physical activity (PA) post-diagnosis brings significant health benefits, enhancing breast cancer survivors' (BCS) prognosis and overall health-related quality of life (HRQoL). Despite these benefits, a low percentage of Chinese BCS adhere to the recommended moderate-to-vigorous PA levels. This highlights the need for innovative PA interventions tailored for BCS management. eHealth technology, such as fitness wearables and apps, presents an opportunity to improve BCS healthcare by offering personalized exercise programs. MethodsThis study focuses on developing a precision eHealth PA program for 200 Chinese BCS in Guangdong Province, using a custom micro-application and a smart band for a 12-month trial. All participants will receive a Huawei Smart Band and be divided into 1) a personalized intervention group, receiving daily PA tracking and feedback, and 2) a control group receiving standard care. The primary outcome is PA and secondary outcomes include biomarkers, weight and body composition, functional fitness, HRQoL, and individual beliefs. Outcomes will be assessed at baseline, 6 months, and 12 months (endpoint). Successful outcomes could revolutionize PA programs for Chinese BCS, providing a model for future eHealth interventions.