This research was conducted to explore how a cognitive reappraisal intervention influences depression in college students with depressive tendencies, as well as to examine how regulatory emotional self-efficacy mediates this link. An unstructured questionnaire was utilized to evaluate the effects of a cognitive reappraisal intervention, while online reading and writing tasks were implemented to address the depressive symptoms among college students exhibiting tendencies. The participants in the study included 98 college students exhibiting depressive tendencies. The students’ depression, regulatory emotional self-efficacy, and cognitive reappraisal scores were measured before and after the intervention. The findings indicated that interventions focused on cognitive reappraisal can effectively reduce depression in college students exhibiting depressive tendencies. Additionally, regulatory emotional self-efficacy played a significant mediating role in the link between cognitive reappraisal intervention and depression levels among these students. The results provide valuable insights regarding interventions for depressive tendencies, highlighting their crucial role in enhancing the mental well-being of college students.