ObjectiveThe aim of this study was to investigate whether there was a difference in survival after initial percutaneous coronary intervention (PCI) among ST-segment elevation myocardial infarction (STEMI) patients with different body mass index (BMI). MethodsLiterature retrieval was conducted on PubMed, Web of Science, Embase, CNKI, and Wanfang databases to obtain the published studies on the survival of STEMI patients with different BMI after initial PCI from the establishment of the database to 2022. All statistical analyses were performed using STATA16.0. ResultsTwo hundred thirty-nine studies were retrieved, and 12 studies were eventually included. Meta-analysis showed that overweight patients [OR = 0.66, 95% CI (0.58, 0.76), p < .001] and obese patients [OR = 0.60, 95% CI (0.51, 0.72), p < .001] had lower in-hospital mortality than healthy-weight patients. Overweight patients [OR = 0.66, 95% CI (0.58, 0.74), p < .001] and obese patients [OR = 0.62, 95% CI (0.53, 0.72), p < .001] had lower short-term mortality than healthy-weight patients. In addition, overweight patients [OR = 0.63, 95% CI (0.58, 0.69), p < .001] and obese patients [OR = 0.59, 95% CI (0.52, 0.66), p < .001] also had lower long-term mortality than healthy-weight patients. There was no significant difference in in-hospital mortality [OR = 1.06, 95% CI (0.89, 1.27), p > .05], short-term mortality [OR = 1.04, 95% CI (0.89, 1.22), p > .05], and long-term mortality [OR = 1.07, 95% CI (0.95, 1.20), p > .05] between overweight and obese patients. ConclusionThis meta-analysis confirmed an obesity paradox in STEMI patients following PCI. The obesity paradox exists in in-hospital, short-term, and long-term conditions.