High-grade ductal carcinoma in situ of breast can be treated by surgery, chemotherapy, endocrine therapy, radiotherapy and targeted therapy. 1. Surgery: the first choice of treatment, including mastectomy with breast preservation, modified radical mastectomy, total mastectomy and so on. 2. Chemotherapy: chemotherapy such as epirubicin and cyclophosphamide can delay tumor recurrence and improve patient’s prognosis under physician’s guidance. 3. Endocrine therapy: for patients with high estrogen receptor content in high-grade ductal carcinoma in situ, tamoxifen and other drugs can be used under the guidance of physicians. 4. Radiotherapy: For patients with high-grade ductal carcinoma in situ who have undergone breast-conserving surgery, local radiotherapy can reduce the risk of tumor recurrence and metastasis. 5. Targeted therapy: patients with HER2 overexpression of high-grade ductal carcinoma in situ can be treated with trastuzumab after surgery, which can reduce the risk of recurrence and metastasis of breast cancer after surgery. High-grade ductal carcinoma in situ of the breast should go to the hospital for timely consultation and early treatment to avoid further development of the disease.