ABSTRACT
Moral injury is a kind of trauma symptom caused by the impact of external immoral events on the internal moral value system of individuals or groups. Its origin lies in the deviation between individual’s internal moral schema and external moral situation. As a collection of moral consciousness units with value orientation in the regular activities of individuals in the moral environment, moral schema is composed of periphery and core. Moral schema realizes the domination of moral ego by supervising individual’s speech and behavior, exercising moderate control over individuals based on moral practice, and examining individual behavior with self-guilt as the tool of judgment. Moral schema is selective about what happened and acts as a filter for trauma events. Based on this, individuals can interpret or be subverted by moral events, thus playing a preventive role in moral injury.