Breast cancer is one of the most common malignant tumors among women, and its treatment is mostly based on the different staging of patients, with adjuvant therapy applied after surgery for patients who can be operated in early stage, surgery after preoperative neoadjuvant therapy for locally advanced breast cancer, and systemic drug and symptomatic treatment for patients who are not suitable for surgery or recurrence in late stage. Targeted therapy for breast cancer is the hot spot for precision treatment. Targeted therapy means that the drug enters the body and specifically binds to the cancer-causing site, thus causing the specific death of tumor cells without affecting the normal tissue cells around the tumor. The most representative targeted therapy for breast cancer is for patients with human epidermal growth factor receptor-2. In breast cancer, about 20% of patients have amplification of the human epidermal growth factor receptor-2 gene or overexpression of its protein, and the prognosis for such patients tends to be poor. Targeted therapies are used to achieve therapeutic goals by activating the receptor gene present in estrogen receptor-negative cells or by introducing an active gene into breast cancer cells. For human epidermal growth factor receptor 2-positive patients with stage II or higher stage, targeted therapy with anthracycline sequential purple shirt combined with Herceptin is usually used, which can significantly improve the survival rate of patients. And the patients need to be clarified as amplified or overexpressed human epidermal growth factor receptor-2 gene by immunohistochemistry and fluorescence immunohybridization method before treatment.