Abstract: The United Nations Sustainable Development Goal proposes to achieve universal health coverage by 2030， and the key element is that everyone can enjoy high-quality healthcare services. Cardiovascular diseases， predominantly acute coronary syndromes， have become the largest disease burden on global health. However， the quality of healthcare services for acute coronary syndromes varies significantly across the populations and regions. This study aimed to investigate the difference in the quality of acute coronary syndrome services in multiple countries， regions， hospitals， and patient populations， and then determine the impact of quality improvement initiatives on quality disparity， which may facilitate further improving the equity of clinical service quality for acute coronary syndromes and promoting health equity and universal health coverage.