BACKGROUND AND PURPOSE: Current guidelines for acute ischemic stroke (AIS) treatment recommend a lenient upper blood pressure (BP) threshold of 185/110 mmHg. However, stricter BP control has been reported to improve prognosis. This study aims to identify the optimal BP range following thrombolysis. METHODS: This observational study included 340 AIS patients treated with rt-PA thrombolysis at the First Affiliated Hospital of Wenzhou Medical University from December 2017 to December 2021. BP levels 24 h after thrombolysis were analyzed to determine their association with clinical outcomes. BP parameters included mean BP, variability (standard deviation (SD)), and decreased magnitudes. The primary outcome was the 90-day modified Rankin Scale (mRS) scores. RESULTS: Higher mean systolic BP (SBP) was associated with poorer outcomes, with adjusted odds ratios (aORs) of 1.25 (95% CI, 1.03-1.51), 1.23 (1.01-1.49), and 1.25 (1.02-1.52) per 10 mmHg increase within 0-2 h, 2-6 h, and 6-24 h post-thrombolysis, respectively, but not for BP variability and decrease magnitudes. Significant improvements in outcomes were observed when the mean SBP was maintained within the range of 120-140 mmHg during both the 0-2 and 2-6 h periods, with aORs of 0.12 (95% CI, 0.02-0.75) and 0.19 (0.04-0.82), respectively. Larger decreases in SBP within 6 h post-thrombolysis were associated with a lower risk of intracerebral hemorrhage. These findings were consistent across subgroups and sensitivity analyses. CONCLUSIONS: Achieving sustained low SBP levels (120-140 mmHg within the first 6 h) over 24 h is linked to better outcomes in thrombolyzed AIS patients.