Objective To investigate the quality of life at one year after percutaneous coronary intervention (PCI) in the elderly patients with coronary heart disease (CHD) and to analyze its influencing factors and correlation with frailty. Methods A total of 166 elderly CHD patients who underwent PCI for the first time in Qionghai People′ s Hospital between January 2021 and January 2022 were included as the study subjects. Their quality of life and frailty were investigated before PCI and at one year after PCI. The data was processed with SPSS statistics 19.0. According to the data type, analysis of variance, t test or Chi-square test was used for comparison between groups. The factors affecting the postoperative quality of life in patients were analyzed by multivariate linear regression model. Pearson correlation analysis was employed to analyze the correlation between frailty and quality of life. Results At one year after PCI, the scores of physical health and psychological health and total score of quality of life scale of elderly CHD patients increased compared with before the surgery (P<0.05). Multivariate linear regression analysis found that gender, living alone, marital status, smoking after surgery and types of underlying diseases were negatively correlated with quality of life in the elderly CHD patients after PCI(β=-0.153, -0.136, -0.173, -0.383, -0.125; P<0.05), and that psycho-social adaptation ability, health education and physical exercise were positively correlated with quality of life(β=0.165,0.056,0.189；P<0.05), which together explained 63.4% of the variance of quality of life in elderly CHD patients at 1 year after PCI (F=58.484, P<0.001). The incidence rate of frailty was 24.10% (40/166), and the score of frailty scale was negatively correlated with quality of life (r=-0.411; P<0.001). Conclusion The quality of life in the elderly CHD patients after PCI is significantly improved compared with before the surgery. Actively carrying out health education, improving bad habits and strengthening exercise are of some value in enhancing the patients′ quality of life.