After treatment, the five-year survival rate of stage I breast cancer is about 95%, and the overall prognosis is good. Breast cancer is a malignant tumor that occurs more often in women and can be caused by various factors such as heredity and hormone level, etc. Stage I is the early stage of the disease, which represents the situation that the maximum diameter of the tumor is less than or equal to 2 centimeters; there is no metastasis in lymph nodes; and there is no distant metastasis. In this period, most of the tumors can be treated by radical surgical resection, and then supplemented with radiotherapy, endocrine therapy or targeted therapy according to the condition after surgery. After active treatment, stage I breast cancer can achieve a better prognosis, with a five-year survival rate of about 95%. Although the stage is early, patients still need to pay attention to regular review as prescribed by the doctor, and maintain good habits in daily life in order to minimize recurrence and prolong survival time.