Objective：To investigate the efficacy and safety of intravenous thrombolysis in elderly patients（≥80 years）with branch atheromatous disease（BAD）. Methods：Old patients with BAD admitted to the Nanjing Brain Hospital Affiliated to Nanjing Medical University from January 2021 to June 2024 were retrospectively collected and divided into 60-79 years old group and ≥80 years old group according to age. Clinical data，early neurological impairment，and 90 d outcomes（including efficacy and safety）were compared between the two groups. Results：A total of 156 patients were included in this study，divided into 60-79 years old group（n=114） and ≥80 years old group（n=42）. The ≥80 years old group had higher baseline brain natriuretic peptide（BNP），prothrombin time（PT） and D-dimer levels than those of the 60-79 years old group（all P < 0.05）. In the effectiveness analysis，compared with the 60-79 years old group，NIHSS scores at 24 h and 7 d after intravenous thrombolysis in ≥80 years old group were higher. There were significant differences between the two groups（all P < 0.05）. Meanwhile，≥80 years old group was more likely to experience early neurological deterioration（END）（38.1% vs. 12.3%，P=0.025）. There were no significant differences in 90 d mRs scores，90 d NIHSS scores，and the proportion of mRs≤2 and mRs≥4 between the two groups（all P > 0.05）. In addition，in the safety analysis，there was no statistical significance in the parenchymal hemorrhagic transformation and gastrointestinal bleeding between the two groups（all P > 0.05），while the proportion of mucosal hemorrhage and stroke-related pneumonia（SAP）in ≥80 years old group was higher than that in 60-79 years old group，with statistically significant differences（all P < 0.05）. Conclusion：Patients ≥80 years with BAD can still benefit from intravenous thrombolysis，but END and complications need to be concerned.