Objective To investigate the relationship between PAI-1 gene polymorphism and cerebral venous thrombolysis occlusion. Methods A total of 232 patients with acute ischemic stroke who received RT PA intravenous thrombolysis in our hospital were selected as the research objects. According to whether the patients had reocclusion or hemorrhagic transformation (HT), they were divided into reocclusion rate group (41 cases), HT group (36 cases) and control group (155 cases). The serum PAI-1 level and PAI-1 gene 675 polymorphism were compared between the two groups, and the serum PAI-1 levels of patients with different genotypes were analyzed. Results The serum PAI-I level in the reoxygenation group was significantly higher than that in the control group, while the serum PAI-I level in HT group was significantly lower than that in the control group (P<0.05). Genotype analysis showed that the proportion of patients with 4G/4G genotype in the reocclusion group was significantly higher than that in the control group, while the proportion of patients with 4G/4G in HT group was significantly lower than that in the control group, the difference was statistically significant (P<0.05). Conclusion The level of PAI-1 in patients with acute ischemic stroke after thrombolytic therapy with RT PA is closely related to the level of serum PAI-1, and 4G / 4G at 675 site of PAI-1 gene is an important factor affecting the level of PAI-1, which may be the main reason for the difference of therapeutic effect after thrombolytic therapy with rt-PA.