Non-specific invasive carcinoma of the breast is classified into 3 grades, which are histologically graded mainly on the basis of three items: the degree of glandular duct formation, nuclear pleomorphism, and the ability of nuclear division. Breast cancer can be divided into non-invasive carcinoma, invasive specific carcinoma and invasive non-specific carcinoma. If the cancer cells are confined to the epithelium and do not break through the basement membrane, it is called non-invasive carcinoma; if the cancer cells invade the basement membrane, it is called invasive carcinoma. Invasive non-specific carcinoma is the most common type of breast cancer. The grading of non-specific invasive carcinoma of the breast is consistent with the grading of other breast cancers, which are all divided into 3 grades. The grading of breast cancer is histologic grading, which is evaluated according to three items: the degree of glandular duct formation, cell nuclear pleomorphism, and the ability of nuclear division, each of which can be rated as a score of 1-3. Those with a total score of 3~5 are classified as grade I, which is highly differentiated cancer with good differentiation, low malignancy and better prognosis; those with a total score of 6~7 are classified as grade II, which is moderately differentiated, medium degree of differentiation, medium degree of malignancy and medium prognosis; and those with a total score of 8~9 are classified as grade III, which is low-differentiated cancer, poorly differentiated, with a high degree of malignancy and poorer prognosis. It is recommended that the patient should consult the doctor in time and follow the doctor’s instruction for further examination and treatment.