Abstract: Objective  To study the efficacy and safety of  different dose reteplase therapy in patients with acute cerebral infarction. Methods  The study was a casecontrol study. In accordance with the thrombolytic conditions prescribed by the Chinese guidelines for cerebrovascular prevention and treatment, patients with acute cerebral infarction within 6 hours of the onset time were treated with different doses of rPA (0.9 mg/kg or 0.6mg/kg) intravenous thrombolytic therapy. NIHSSbaseline， 24 hours after thrombolysis NIHSS， the mortality after three months and the incidence of symptomatic intracranial hemorrhage(sIcH)  were compared. Results  ① NIHSS score， time of onset， time of thrombolytic therapy and coagulation function after 12 hours were not statistically significant (P>0.05). ② NIHSS and 24 hours after thrombolysis NIHSS in different doses of thrombolysis were significantly reduced（P＜0.05). ③The incidence of sIcH  in two different dosage groups， the mortality rate within 24 hours after thrombolysis and NIHSS and three months after thrombolysis were not statistically significant (P>0.05).Conclusion  Different doses of rPA (0.9  mg/kg or  0.6  mg/kg) are both effective in thrombolytic therapy for acute cerebral infarction. Furthermore， there was no statistical difference between different doses in sIcH.

Key words: brain infarction, reteplase, intracranial hemorrhages, low dose