Objective: To investigate the anxiety of elderly patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) and analyze the influencing factors. Methods: A total of 276 elderly patients with ACS in Navy PLA General Hospital from February 2017 to February 2018 were selected by the convenience sampling method, all patients underwent PCI surgery, a self-designed elderly patients with ACS after PCI anxiety survey questionnaire was used to investigate anxiety of them, single factor analysis and multivariate logistic regression analysis were used to analyze the factors influencing anxiety in patients. Results: The female anxiety score was significantly higher than that of men in the age group of 60–75 years. Men over 75 years old have higher anxiety than men aged 60–75 (P<0.05). Anxiety score of men over 75 years old was higher than that of men aged 60–75, while anxiety score of female patients aged 60–75 years was higher than that of female patients older than 75 years (P<0.05). Logistic regression analysis showed that sex (OR=1.713), age (OR=1.623), exercise intensity (OR=1.436), exercise time (OR=1.323) and living status (OR=1.315) were risk factors of anxiety of elderly patients with ACS after PCI (P<0.05). Conclusion: There are differences in the anxiety level of patients with ACS after PCI at different ages and sex. We may try to reduce the anxiety through targeted social support and reasonable exercise.