Objective To evaluate the efficacy and safety of alteplase (rt-PA) thrombolytic therapy on patients with acute ischemic stroke aged over 80 years old.Methods The observational cohort study were conducted.One hundred and thirty-six patients with acute cerebral infarction and received rt-PA thrombolytic treatment were selected as our subjects with incidence time of 4.5 h,and the rt-PA dose of 0.9 mg/kg.The patients were divided into ≥80 years old group(n =34) and ＜80 years old group(n =102).U.S.A national institutes of health stroke scale (NIHSS) score of two groups evaluated before thrombolysis,immediately after thrombolysis 24 h,7 d and 14 d.The incidence and mortality rate of intracranial hemorrhage (ICH) and symptomatic intracranial hemorrhage (sICH) of two group were compared; and the score of modified Rankin's Scale (mRS) followed-up of 90 d were evaluated.Results NIHSS score after thrombolysis 24 h,7 d and 14 d of two groups were significantly lower than that before thrombolysis,and the differences were statistically significant (t =4.123,9.936,9.679,5.657,8.154,6.956,P ＜0.01).The score after thrombolysis 24 h,7 d and 14 d of two groups were no statistically significant difference.The efficient rate of treatment of two group were 55.88％ and 61.76％ respectively(P =0.54).Mter follow-up of 90 d,the prognosis rate were 47.06％ and 64.71％ respectively(P =0.07),and there were no statistically significant difference.Incidence rate of ICH were 11.76％ and 5.88％ respectively(P =0.07).Occurrence rates of sICH were 5.88％ and 2.94％ (P =0.43).Mortality rate were 11.76％ and 9.80％ (P =0.33),and there were no statistically significant difference.Conclusion This study shows that 80 years of age or older patients with acute ischemic cerebral apoplexy patients using rt-PA intravenous thrombolytic therapy is safe and effective,but RCT need further study.