Inclusion Criteria1. Age 18 to 80 years old;
2. First time diagnosed or have history of acute anterior circulation cerebral infarction without serious sequelae (mRS = 0-2);
3. Acute anterior circulation cerebral infarction with large artery atherosclerotic etiology;
4. Ability to randomize within 48 h of time last known free of new ischemic symptoms.
5. National Institute of Health stroke scale(NIHSS) ranges from 7 to 22;
6. signed written informed consent.
Exclusion Criteria1. Cerebral CT shows cerebral hemorrhage disease: cerebral hemorrhage, subarachnoid hemorrhage, etc.;
2. Transient ischemic attack;
3. Serious disturbance of consciousness: Glasgow Coma ScaleGCS（GCS）≤8;
4. Combined angiotensin-converting enzyme inhibitor(ACEI) less than 5 half-time (according to its instruction), or need to be treated with ACEI;
5. Past or present suffering from hemorrhagic tendency of the disease;
6. The investigator in consideration of the other condition that the patients doesn't fit to participate in this clinical study.