After successful coronary angiography and OCT examination, patients with TCFAs in non-culprit, mild-to-moderate stenotic lesions will be enrolled. Then, they will be randomly assigned in a 1:1 ratio to receive either atorvastatin (20 mg/day) alone or atorvastatin (20 mg/day）plus ezetimibe（10 mg/day）by envelope method. Angiographic and OCT follow-up will be scheduled for the target vessel after 12 months.

This is a prospective, randomized , controlled, open-label, single-center study to evaluate the effect of ezetimibe added to atorvastatin on coronary thin-cap fibroatheroma(TCFA). After successful coronary angiography and OCT examination, patients with TCFAs in non-culprit, mild-to-moderate stenotic lesions will be enrolled. Then, they will be randomly assigned in a 1:1 ratio to receive either atorvastatin (20 mg/day) alone or atorvastatin (20 mg/day）plus ezetimibe（10 mg/day）by envelope method.

Angiographic and OCT follow-up will be scheduled for the target vessel after 12 months.The primary efficacy endpoint is the change in minimum fibrous cap thickness measured by OCT from baseline to follow-up.The secondary endpoints include absolute and percent changes in the lipid, glycemic, and inflammatory profile. Then, changes of these indicators above will be compared respectively in diabetic and non-diabetic patients.

Inclusion Criteria:

1.stable angina or acute coronary syndrome 2.18-80 years old 3.hypercholesterolemia :total cholesterol level >220 mg/dl (5.7mmol/L) and/or LDL-C level >140 mg/dl(3.6mmol/L), or previously receiving statins therapy 4. the target vessel for OCT interrogation has not undergone angioplasty and has angiographic diameter stenosis from 25% to 75% 5.There are TCFAs in non-culprit, mild-to-moderate stenotic lesions above

Exclusion Criteria:

1. administration of lipid-lowering drugs other than statins before enrollment
2. significant stenotic lesions in all coronary vessels
3. severe congestive heart failure (New York Heart Association class IV) ,or left ventricular ejection fraction<35%
4. more than 3 times of the upper limit of normal (ULN) in the creatine kinase (CK) and the transaminase level before enrollment and no relation with myocardial infarction
5. renal failure (serum creatinine>2.0 mg/dL）
6. hypersensitivity to x-ray contrast media, statin，clopidogrel or ezetimibe
7. Others: terminal stage cancer,a positive pregnancy test