Background: Developing guidelines for the diagnosis and treatment of common cancers in China based on the evidence-based practice, the availability of diagnosis and treatment products, and the up-to-date advances in precision medicine is one of the basic tasks of the Chinese Society of Clinical Oncology Breast Cancer (CSCO BC) Committee. Methods: Protocols with high evidence level and good availability are used as the Level I recommendations; protocols with relatively high evidence level but slightly lower expert consensus or with poor availability are used as the Level II recommendations; and protocols that are clinically applicable but with low evidence level are regarded as the Level III recommendations. Based on the findings of clinical research at home and abroad and the opinions of CSCO BC experts, the CSCO BC guidelines determine the levels of recommendations for clinical application. Results: For human epidermal growth factor receptor 2 (HER2)-positive breast cancer, a combination of trastuzumab and pertuzumab regimen were recommended as Level I recommendation for neoadjuvant and first line metastatic breast cancer. Pyrotinib is also recommended as Level I recommendation in first line and second line therapy according to the latest studies conducted in China. Antibody drug conjugates was also recommended for patients with trastuzumab progression. For triple negative breast cancer, immunotherapy in early and metastatic breast cancer was highlighted and listed as new chapters in this version of guideline. For hormone receptor (HR)-positive breast cancer, cyclin dependent kinase 4/6 (CDK4/6) was recommended in different stages, especially in adjuvant therapy. There was also a new chapter for HER2-low breast cancer stratified by HR status. Conclusions: We firmly believe that evidence-based, availability-concerned, and consensus-based guidelines will be more feasible for clinical practice in China and in other countries with similar situations.