Intermediate grade intraductal breast cancer with mesenchymal infiltration is a kind of breast cancer. Intermediate grade suggests that the tissue is poorly differentiated and the cancer cells are more invasive and metastatic; mesenchymal infiltration indicates that the cancer foci have exceeded the epithelium of breast ducts, which is invasive ductal cancer. Intermediate-grade intraductal carcinoma of the breast with mesenchymal infiltration can be treated by surgery, and adjuvant radiotherapy or chemotherapy is needed to consolidate the effect of surgery after surgery. In addition, the treatment methods include targeted therapy, endocrine therapy and chemotherapy. The earlier the disease is detected, the higher the chance of 5-year survival. If diagnosed with intermediate-grade intraductal breast cancer with interstitial infiltration, it is recommended to go to the hospital in time for targeted treatment under the doctor’s guidance.