Inclusion Criteria:
1. 18 to 80 years of age;
2. Diagnosis of anterior circulation acute ischemic stroke;
3. Within 48 hours of symptoms onset;
4. modified Rankin Scale (mRS) score≤1 before this event;
5. 5≤NIHSS≤20 at screening;
6. The availability of informed consent.
Exclusion Criteria:
1. Patients who have already or are going to receive intravenous thrombolytic/mechanical thrombectomy therapy after onset;
2. Patients with severe consciousness disorder, NIHSS 1a consciousness level score≥2;
3. Patients with limited limb mobility such as fractures and claudication upon admission;
4. Patients who have already or are going to receive Edaravone injection, Edaravone and DeKanol concentrated solution for injection, Butylphthalide and sodium chloride injection or Butylphthalide soft capsules after onset;
5. Hypotensive (systolic blood pressure \<90 mmHg or diastolic blood pressure\<60 mmHg) on admission;
6. History of severe drug or food allergy, allergy or intolerance to Human Urinary Kallidinogenase;
7. Patients who have been on angiotensin-converting enzyme inhibitor (ACEI) drugs and within 5 half-lives (according to the specific drug instructions) before initiate Human Urinary Kallidinogenase treatment;
8. Pregnancy, lactation, or planned pregnancy within 90 days;
9. Patients with severe renal failure or impairment (eGFR\<30ml/min/1.73m2) at screening;
10. Severe hepatic dysfunction, elevation of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) (more than 2.5 times of upper limit of normal value), other liver diseases such as acute and chronic hepatitis, cirrhosis, etc;
11. Patients with heart failure (NYHA class III or IV), unstable angina pectoris, acute myocardial infarction, severe arrhythmia, and degree II and III cardiac conduction obstruction within 6 months prior to randomization;
12. Heavy drinking in the three months before screening, drinking≥5 standard drinks per day (1 standard drink is equivalent to120ml wine, 360ml beer or 45ml liquor);
13. Drug Abuse or addiction in the past year;
14. Patients with a malignant tumor, severe systemic diseases, or estimated survival time \<90 days;
15. Patients with severe mental disorders or dementia unable to complete the informed consent and follow-up;
16. Have participated in another interventional clinical study within 30 days before randomization or are participating in another interventional clinical study;
17. Other cases unsuitable for this clinical study assessed by researcher.
