Objective To investigate the effectiveness and safety of intravenous thrombolytic therapy with low-dose alteplase for elderly patients with acute ischemic stroke.Methods The elderly patients with acute ischemic stroke were enrolled prospectively (onset within 4.5 h,aged ≥75 years).They were randomly divided into either a low-dose group (0.6 mg/kg) or a standard-dose group (0.9 mg/kg).The primary outcome was the modified Rankin Scale (mRS) score determined the good outcome (mRS score 0-2) and poor outcome (mRS score ＞2) at 90 d after treatment;the secondary outcome was intracranial hemorrhage and symptomatic intracranial hemorrhage at 24 h after thrombolysis,and death within 90 d.Results A total of 65 elderly patients with acute ischemic stroke were enrolled,including 32 in the low-dose group and 33 in the standard-dose group.There were no significant differences in all baseline clinical data between the two groups.Compared with before treatment,the proportions of patients with the mRS score 0-2 were significantly higher in both groups at 7 d,14 d,and 90 d after treatment,but there were no significant differences in good outcome rate at the same time point after treatment between the two groups.In addition,there were no significant differences in intracranial hemorrhage (36.4％ vs.25.0％;x2 =0.985,P =0.321),symptomatic intracerebral hemorrhage (21.2％ vs.9.4％;x2 =1.749,P =0.186) at 24 h after treatment,and incidence of death within 90 d after treatment (12.1％ vs.6.3％;x2 =0.151,P=0.697)between the two groups.Conclusions The effectiveness and safety of intravenous thrombolytic therapy with low-dose alteplase (0.6 mg/kg) in elderly patients with acute ischemic stroke is equivalent to the standard dose.