Phase III Study ：SHR6390/Placebo Combined With Endocrine Therapy for the Adjuvant Treatment of Hormone Receptor Positive,Human Epidermal Receptor 2 Negative

Inclusion Criteria: 1. Postmenopausal or premenopausal/perimenopausal female patients aged ≥18 years and ≤75 years old. 2. Pathological examination diagnosed as invasive breast cancer with HR+ and HER2-. 3. Underwent radical resection of breast cancer. 4. The score of ECOG was 0 - 1. 5. Fertile women must have a negative serum pregnancy test within 7 days before randomization, and be willing to use acceptable non hormonal contraceptive measures. 6. With my consent and informed consent, I am willing and able to comply with the planned visit, study treatment plan, laboratory examination and other test procedures. Exclusion Criteria: 1. This Pathological examination diagnosed as HER2-positive breast cancer. 2. The history of any malignant tumor other than breast cancer within 5 years before randomization. 3. At the same time participate in other anti-tumor therapy clinical trials (including endocrine therapy or immunotherapy, etc.). 4. In the 6 months before randomization, the following conditions occurred: myocardial infarction, severe/unstable angina pectoris, , etc 5. Inability to swallow, intestinal obstruction, or other factors that affect the administration and absorption of the drug. 6. There are other serious physical or mental illnesses or laboratory abnormalities that may increase the risk of participating in the study, or interfere with the results of the study, as well as patients who the investigator believes are not suitable for participating in this study.