In this study, the investigates try to confirm the hypothesis that low dose ticagrelor(60mg) had similar anti-platelets function compared with the standard dose ticagrelor in acute coronary syndrome patients with diabetes. Totally 40 ACS patients with diabetes will be divided into 2 groups randomly after PCI for one month. Group 1 will be treated with ticagrelor 90mg and aspirin 100mg after PCI for 12 months as the standard group; Group2 will be treated with ticagrelor 60mg plus aspirin 100 mg for 11 months after one month standard DAPT treatment. The platelets function will be tested in VASP and TEG methods at 1 and 2 months after PCI as the primary endpoints.The clinical events will be observed 12 months after PCI.

Inclusion Criteria:

1. Subject must be at least 18 years of age and less than 90 years old
2. Patients should have undergone successful percutaneous coronary intervention with drug-eluting stent for acute coronary syndrome with diabetes mellitus.
3. Subject understand the study requirements and the treatment procedures and
4. provided informed consent before the procedure

Exclusion Criteria:

1. Female of childbearing potential, unless a recent pregnancy test is negative, who possibly plan to become pregnant any time after enrollment into this study
2. Active bleeding
3. Known hypersensitivity or contraindication to study medications
4. Female of childbearing potential, unless a recent pregnancy test is negative, who possibly plan to become pregnant any time after enrollment into this study
5. Non-cardiac co-morbid conditions are present with life expectancy <2 year or that may result in protocol non-compliance (per site investigator's medical judgment).
6. Subjects with Cerebral hemorrhage history
7. Subjects with stroke history in half a year
8. subjects with active malignant tumor
9. subjects with whom oral anticoagulants are needed
10. Other conditions which the investigators think not applicable to the study.