Objective To identify the level and determinants of moral courage among ICU nurses. Methods A total of 422 ICU nurses in Sichuan province were conveniently selected and invited to fill out a self-designed demographic data questionnaire, the Nurses′Moral Courage Scale, the Psychological Empowerment Scale (PES) and the Hospital Ethical Climate Survey (HECS). Results The total moral courage score of ICU nurses was （83.96±13.91）. Multivariate regression analysis showed participation in clinical teaching, dimensions of self-efficacy and job impact in the PES, and dimension of relationship with patients in the HECS were predictors of moral courage of ICU nurses,which could explain 55.7% of the overall variance (all P<0.05). Conclusion ICU nurses report medium-to-high level of moral courage, which is affected by personal factors and hospital environment. Nursing managers should take measures to improve ICU nurses′ psychological empowerment and create an ethical climate, thus to enhance their moral courage and alleviate moral distress and ethical conflict.