Objective To investigate the efficacy and safety of low-dose and standard-dose intravenous alteplase for acute ischemic stroke. Methods The patients with acute ischemic stroke treated with intravenous alteplase from August 2012 to January 2016 were analyzed retrospectively. According to the dosage of the drug, the patients were divided into either a low-dose group (0. 6-0. 8 mg/kg) or a standard-dose group (0. 9 mg/kg). The efficacy was evaluated with the modified Rankin Scale (mRS) at 90 days, and a favorable functional outcome was defined as mRS 0-1. The safety was evaluated by the mortality at 90 days and the incidence of symptomatic intracerebral hemorrhage (SICH) within 7 d after onset. Results A total of 790 patients were enrolled, including 612 in the low-dose group and 178 in the standard-dose group. There was no significant difference in each baseline clinical data between the 2 groups. Compared with the standard-dose group, there was no significant difference in the good outcome rate of the small-dose group at day 90 (35. 6% vs. 37. 6% ; χ2 = 0. 872, P = 0. 35) and mortality (5. 1% vs. 6. 2% ;χ2 = 2. 173, P = 0. 14), but the incidence of SICH was significantly lower (1. 8% vs. 5. 1% ; χ2 = 5. 875, P =0. 015). Conclusion The efficacy of low-dose intravenous alteplase for acute ischemic stroke is equivalent to the standard-dose and the safety is better.