Abstract: Objective To explore the relationship between college students' understanding social support and depression and emotion regulation mode in one of the intermediary role,and to provide basis for maintenance and promotion of college students metal health.Methods Using the "understanding social support scale","self rating depression scale" and "GROSS way emotion regulation questionnaire to Zhanjiang to survey 1 080 college students.Results The girl college students' understanding social support (5.21±0.88) and depression score(1.95±0.34) were significantly higher than the boys' (5.05±0.92;1.89±0.36) (t =-4.52,-3.99,P<0.01),the city students' depression score(1.95±0.35) was significantly higher than rural students (1.92±0.34) (P<0.05),the liberal arts students' depression score(1.96±0.34) was significantly higher than science students'(1.91±0.34) (t=2.15,-3.47,P<0.01);About the emotion regulation strategies were significant difference in demographic variables(P<0.05).Zhanjiang students' understanding social support and depression levels had significantly negative correlation (r=0.38,P<0.01),and cognitive reappraisal strategy had significant positive correlation(r=0.22,P<0.01),and negatively correlated with expression suppression strategy(r=0.10,P<0.05);Zhanjiang college students' level of depression and cognitive reappraisal,had significant negative correlation(r=-0.25,P<0.01),and the expression suppression were positively correlated(r =0.10,P<0.05);the students' cognitive reappraisal in understanding with intermediary effect between social support and depression,their emotion regulation way in understanding had partial intermediary role between social support and depression.Conclusion The use of the college students' cognitive reappraisal strategy play the intermediary role between social support and depression.