Objective To investigate the predictive value of serum microRNA （miRNA） -143-3p and miR-188-5p levels for poor prognosis in patients with acute cerebral infarction （ACI） after thrombolysis. Methods From February 2022 to February 2024， 121 patients with acute cerebral infarction （ACI） who visited the hospital （all treated with thrombolysis） were selected as the study group. They were assigned into mild and moderate to severe groups based on the severity of their condition. They were into good prognosis group and poor prognosis group based on their postoperative condition. In addition， another 121 healthy individuals who underwent physical check ups during the same period were as the control group. The qRT-PCR method was applied to detect the expression levels of miR-143-3p and miR-188-5p. Pearson correlation was applied to analyze the correlation between serum miR-143-3p， miR-188-5p and NIHSS score. The influencing factors of poor prognosis in ACI patients after thrombolysis were analyzed using multiple logistic regression. ROC curve was plotted to analyze the predictive value of serum miR-143-3p and miR-188-5p for poor prognosis after thrombolysis in ACI patients. Results The serum miR-143-3p level in the study group was higher than that in the control group （P < 0.05）， and the miR-188-5p level was lower than that in the control group （P < 0.05）； The serum miR-143-3p and NIHSS score in the mild， moderate and severe groups were increased in turn， and the level of miR-188-5p was decreased in turn （P < 0.05）； Serum miR-143-3p was negatively correlated with miR-188-5p （P < 0.05）； Diabetes， time from onset to thrombolysis， NIHSS score at admission， miR-143-3p and miR-143-3p were the influencing factors of poor prognosis in ACI patients after thrombolysis； The AUC of the joint of serum miR-143-3p and miR-188-5p in predicting poor prognosis after thrombolysis in ACI patients was 0.871， and the joint of the two was better than their individual predictions （Z = 2.683， 2.703， P < 0.05）. Conclusions The level of serum miR-143-3p in ACI patients is significantly increased， and the level of serum miR-188-5p is significantly decreased， which is a poor prognostic factor for ACI patients after thrombolysis. The combination of the two has higher diagnostic value.