Blood pressure (BP) monitored within 24 h from the beginning of intravenous thrombolysis (IVT) with alteplase, is one of the important factors affecting the prognosis of patients with acute ischemic stroke (AIS). This study aimed to explore longitudinal BP trajectory patterns and determine their association with stroke prognosis after thrombolysis. From November 2018 to September 2019, a total of 391 patients were enrolled consecutively during the study period, and 353 patients were ultimately analyzed. Five systolic (SBP) and four diastolic blood pressure (DBP) trajectory subgroups were identified. The regression analysis showed that when compared with the rapidly moderate stable group, the continuous fluctuation-very high level SBP group (odds ratio [OR]: 2.743, 95% confidence interval [CI]: 1.008-7.467) was associated with early neurological deterioration (END). Both the rapid drop-high level SBP (OR: 0.448, 95% CI: 0.219-0.919) and DBP groups (OR: 0.399, 95% CI: 0.219-0.727) were associated with early neurological improvement (ENI). Moreover, there was a U-shaped correlation between the OR value of SBP trajectory group and favorable outcome (the modified Rankin Scale [mRS] score 0-2) at 3 months: the slow drop-low level SBP group represent a well-established unfavorable outcome risk factor (OR:5.239, 95% CI: 1.271-21.595), and extremely high SBP-the continuous fluctuation-very high level SBP group, are equally associated with elevated unfavorable outcome risk (OR:3.797, 95% CI: 1.486-9.697). The continuous fluctuation-very high level DBP group was statistically significant in mRS (OR: 3.387, CI: 1.185-9.683). The BP trajectory groups show varying clinical features and risk of neurological dysfunction. The findings may help identify potential candidates for clinical BP monitoring, control, and specialized care.