Aim To identify the risk factors for no-reflow (NR) associated with post-stenting balloon dilatation (PSBD) among patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI) and their impact on prognosis. Methods This study enrolled 147patients with STEMI who received emergency PCI and underwent PSBD within 12 hours. The patients were divided into the normal flow group and NR group based on their TIMI thrombus scores. Clinical data, angiography characteristics, efficacy after interventional therapy, and major adverse cardiovascular events (MACE) within one year after therapy were analyzed and compared between the two groups. Age, identified time to PCI, length of the offender's blood vessels, number of stent implants, and high-burden thrombus formation were analyzed to explore risk factors for NR after PSBD by regression analysis. The relationship between NR and the occurrence of MACE at one year after operation was analyzed to explore the influence of risk factors on prognosis. Results Sixteen patients (10.88%) had NR after PSBD. Univariate analysis revealed the correlation of age, identified time to PCI, length of the offender's blood vessels, number of stents, and high-burden thrombus formation with the incidence of NR associated with balloon dilatation (P＜0.05). Multiple Logistic analysis revealed that identified time to PCI (OR:0.5,5%CI:0.92～0.99), length of the offender's blood vessels (OR:0.6,5%CI:0.93～0.99) and high-burden thrombus formation (OR:0.4,5%CI:0.03～0.71) were independent risk factors of NR associated with PSBD. Conclusions Prolonged time to PCI, increased length of the offender's blood vessels, and heavy high-burden thrombus formation are positively correlated with the occurrence of NR after PSBD, and are independent risk factor of NR associated with PSBD for STEMI. The incidence of NR after PSBD was positively correlated with the incidence of recurrent angina in 1-year follow up.