Objective：To investigate the factors of spontaneous recanalization（SR）and its impact on long-term prognosis in patients with acute ST -segment elevation myocardial infarction（STEMI）. Methods：The study consecutively enrolled patients diagnosed with STEMI and underwent primary percutaneous coronary intervention in Nanjing First Hospital from July 2011 to April 2019. Patients were divided into the SR group（TIMI flow grade 0-1）and the non -SR group（TIMI flow grade 2-3）based on the results of coronary angiography. The data of the two groups were collected，including general clinical data，laboratory test results，coronary angiography and drug treatment. The primary endpoint was all-cause death. Results：Total 1 124 patients were enrolled，including 272 patients （24.2%）in the SR group and 852 patients（75.8%）in the non-SR group. Patients with SR were significantly decreased in proportions of hypertension，creatine kinase isoenzyme -MB（CK -MB）peak value，creatinine levels，uric acid levels，thrombus vessel aspiration rate，intra-aortic balloon pump（IABP）implantation rate and in-hospital mortality，compared with the non-SR group. However，the left ventricular ejection fraction was higher in the SR group than in the non-SR group. Multivariate logistic regression analysis showed that hypertension was a disadvantage for SR（OR=0.744，95%CI：0.561-0.985，P=0.039）. The follow-up period was 79（61，101）months， during which 124 patients occurred all-cause mortality. Kaplan-Meier curves indicated that there was no significant difference in survival time between the SR group and the non-SR group（log-rank P=0.182）. Multivariate COX regression analysis revealed that age， Killip classification，creatinine，in-hospital IABP implantation，left ventricular ejection fraction，single-vessel disease，ticagrelor and β -blocker were independent predictors of all-cause death in STEMI patients. Conclusion：Nearly 1/4 of STEMI patients occur SR before the primary percutaneous coronary intervention. Hypertension is an unfavorable factor for SR occurrence. However，long -term follow-up reveals that SR does not reduce all-cause mortality in STEMI patients.