Objective: To observe the correlation between early repolarization of electrocardiogram and the prognosis of patients with acute ST-segment elevation myocardial infarction (STEMI) after direct percutaneous coronary intervention (PCI). Methods: The clinical data of 2458 patients with acute STEMI who underwent direct PCI treatment in our hospital from January 2020 to January 2025 were retrospectively collected. The occurrence of major adverse cardiovascular events within 90 days after PCI in patients was statistically analyzed, and the patients were divided into the poor prognosis group and the good prognosis group according to whether adverse cardiovascular events occurred. Collect and compare the baseline data of the two groups. All patients underwent electrocardiogram examination and early repolarization determination of electrocardiogram. To analyze the correlation between the early negative poles of electrocardiogram and the prognosis of STEMI patients after direct PCI. Result: Among 2458 patients with acute STEMI, 262 cases experienced major adverse cardiovascular events within 90 days after direct PCI, accounting for 10.66% (262/2458), and were included in the poor prognosis group. There were 2196 cases without major adverse cardiovascular events, accounting for 89.34% (2196/2458), and they were included in the good prognosis group. Among 2458 patients with acute STEMI, electrocardiogram examination revealed that 352 patients had early repolarization, accounting for 14.32% (352/2458). The age and the proportion of early repolarization of electrocardiogram in the poor prognosis group were significantly higher than those in the good prognosis group (P < 0.05). Logistic regression analysis showed that the prognosis of acute STEMI patients after direct PCI treatment was related to age and early repolarization of electrocardiogram (P < 0.05). The results of the Spearman correlation test showed that the risk of poor prognosis after direct PCI in patients with acute STEMI was positively correlated with early electrocardiogram repolarization (r=0.408, P < 0.05). Conclusion: Acute STEMI patients with early electrocardiogram repolarization have a higher risk of poor prognosis after direct PCI, and there is a positive correlation between the two.