Inclusion Criteria:  Age ≥ 18 years old; Acute ischemic stroke patients who received intravenous thrombolysis within 4.5 hours of onset; NIHSS ≤ 5 within 6 hours after the end of intravenous thrombolysis, and no bleeding transformation was found in head CT examination; Premorbid mRS ≤ 1; Signed informed consent.  Exclusion Criteria:  Premorbid mRS≥2; Uncontrolled severe hypertension (systolic pressure >180 mmHg or diastolic pressure >110 mmHg after drug treatment); Antithrombotic treatment within 24 hours before randomization; Significant dysphagia and inability to take the experimental drug orally; Allergy or contraindication to study drugs; Comorbidity with any serious diseases and life expectancy is less than half a year; Participating in other clinical trials within three months; Patients not suitable for this clinical study considered by researcher