In addition, studies have found that indobufen can inhibit coagulation function in rats. Compared with aspirin, the duration of antiplatelet efficacy of indobufen was shorter, and the platelet function recovered completely 24 hours after drug withdrawal. However, there are few studies on the antiplatelet efficacy of indobufen. The investigators' previous study found that the inhibitory effect of indobufen 100 mg Bid on COX system in atherosclerosis or healthy volunteers was equivalent to that of aspirin 100 mg QD, but the inhibitory effect on platelet COX-1 channel was significantly weaker than that of aspirin 100 mg QD. In view of this, this study intends to investigate the antiplatelet effect of indobufen 200 mg Bid in patients with coronary atherosclerosis by comparing it with conventional-dose aspirin 100 mg QD.

Inclusion Criteria:

1. Clinical diagnosis of coronary atherosclerosis without indications for stent implantation.
2. Age ≥ 18 years, ≤ 65 years
3. Sign informed consent

Exclusion Criteria:

1. A history of asthma or allergic constitution or known allergy to indobufen or aspirin.
2. High risk of bleeding (low hemoglobin 10g / L, history of peptic ulcer disease, fecal occult blood positive or known active bleeding, history of cerebral hemorrhage within 6 months, history of fundus hemorrhage, etc).
3. Creatinine was 1.2 times higher than the upper limit of normal value and ALT was 1.2 times higher than the normal value.
4. History of smoking and alcoholism.
5. History of diabetes.
6. Pregnancy and lactation women.
7. Nonsteroidal anti-inflammatory or other antithrombotic drugs other than indobufen are required.
8. Any other reason may affect the results of this study.