Breast cancer is the most common malignant tumor in women. Surgery, radiotherapy, chemotherapy, endocrine therapy and targeted therapy are common treatment methods. More and more evidence⁃based medicine evidences show that the nutritional status of patients with breast cancer is closely related to the treatment effect, the risk of recurrence, the risk of death and the quality of life. Proper nutritional treatment can not only help breast cancer patients maintain good nutritional status and living habits, increase treatment tolerance, improve treatment effect, improve quality of life, but also reduce the risk of recurrence and death of breast cancer patients. Nutritional monitoring and treatment of breast cancer patients should not be ignored, and should pay equal attention to anti⁃tumor treatment. Overnutrition is associated with a higher incidence in breast cancer patients than undernutrition. Overnutrition can lead to physical impairment, decreased quality of life, increased treatment⁃related adverse reactions, and persistent psychosocial problems. After the diagnosis of breast cancer, nutritional risk screening and nutritional assessment should be carried out, even if effective nutritional treatment measures are taken, and regular follow⁃up should be carried out throughout the disease process.