Background: Intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis therapy has been regarded as a promising therapeutic measure for acute ischemic stroke (AIS). But its effectiveness and safety are unclear because of the lack of large, long-term, prospective and multi-center clinical studies in China. Objective: This study was to explore the efficacy of the therapy, and hypothesize some baseline clinical variables that might affect clinical outcomes.Methods: All patients with AIS were treated by intravenous rt-PA thrombolysis within 4.5 h from stroke onset. The clinical records and laboratory data of pre- and post-treatment were statistically analyzed to testify the efficacy and safety of this treatment and to find out the independent prognostic factors.Results: A total of 1 067 patients were selected in this study and divided into group A (<80 years old, n=769) and group B (≥80 years old, n=298). A favorable outcome was observed in 261 patients in group A and 81 patients in group B, respectively. A total of 6 factors were identified as independent prognostic factors for intravenous rt-PA thrombolysis therapy.Conclusion: rt-PA thrombolysis therapy is effective in treating AIS patients, but there are multiple risk factors that affect prognosis.