Based on the conservation of resource theory, this study examined the effects of interpersonal adaptation on college students'' ego identity and the role of emotional adaptation and psychological capital therein. A moderated mediating effect model was constructed and proved by the data of questionnaire survey. The results shows that: First, there is a significant predictive effect between interpersonal adaptation and emotional adaptation, emotional adaptation and ego identity. Second, emotional adaptation is found to function as partial mediator between interpersonal adaptation and ego identity. Third, the mediating role of emotional adaptation is moderated by psychological capital, meaning that the effect of interpersonal adaptation on emotional adaptation decreases with the increasing psychological capital. These findings will help to effectively prevent and control college students'' emotional adaptation problems and ego identity crisis.