Abstract Funding Acknowledgements None. Background Psychological stress is associated with high incidence of coronary heart disease and increases the risk of mortality and poor health status. Although a few studies have investigated psychological stress in this population, this problem is usually unrecognized and untreated in most Chinese patients with acute coronary syndrome. There is insufficient information regarding the features of psychological stress and associated factors among this population. Purpose This study aimed to assess the level of psychological stress and to identify its correlates in Chinese patients with acute coronary syndrome. Methods Patients aged over 18 years and with acute coronary syndrome were invited to participate in a cross-sectional survey in two tertiary public hospitals in China, from June to July 2019. A total of 332 patients completed measures of sociodemographic and clinical characteristics, psychological stress (10-item Perceived Stress Scale), and illness perception (Brief Illness Perceptions Questionnaire). Independent sample t-tests, bivariate correlations, and multivariable linear regression were performed to analyze potential correlates, including age, gender, education level, employment status, income, episode of illness, revascularization procedure, comorbidities, body mass index, blood pressure, blood glucose, blood lipids, and illness perception. Results The average patient age was 62.2 years, 67.5% were male, and 54.2% had less than high school education. The mean score for psychological stress was 21.30 ± 3.99 and 66.9% of patients had high psychological stress (score ≥ 20). Multivariable regression analysis showed that being overweight/obesity versus normal weight (body mass index: ≥ 24 kg/m2 versus < 24 kg/m2) was associated with lower psychological stress (β = -0.134, p = 0.007). Having a high level of fasting blood glucose (≥ 6.1 mmol/L) versus normal fasting blood glucose (< 6.1 mmol/L) was associated with high psychological stress (β = 0.123, p = 0.017). Additionally, negative cognitive illness perception (β = 0.190, p = 0.01), negative emotional illness perception (β = 0.290, p < 0.001), and poor illness understanding (β = 0.118, p = 0.032) were associated with high psychological stress. Conclusions Patients with acute coronary syndrome experience high psychological stress that is significantly correlated with body mass index, fasting blood glucose, and illness perception. Health professionals should recognize this issue and interventions looking to relive psychological stress may benefit from targeting these correlates.