Abstract: Objective To investigate the epidemic situation and characteristics of depressive symptoms among high school students in Yunnan province and to explore the relationship between depressive symptoms and social support in the students.Methods Using multi-stage stratified random cluster sampling method,12 408 students were selected from 17 high schools in 6 cities,counties or districts in Yunnan province and a questionnaire survey was conducted in the students with a self-designed questionnaire,Center for Epidemiologic Studies Depression Scale(CES-D), and Social Support Rating Scale(SSRS).Results The overall detection rate of depressive symptoms was 23.7%among the 12 206 students with valid respondence.The girl students had a higher depressive symptom detection rate than the boy students(25.6%vs.21.6%,P<0.001);the senior high school students had a higher detection rate than the junior high school students(25.3%vs.22.1%,P<0.001);the non-singleton students had a higher detection rate than singleton students(24.6%vs.21.5%,P<0.001);and no difference in the detection rate was observed among the students of different nationality(P>0.05).There was a significant gender difference in the score of social support utilization(Z=9.67,P<0.001).There were significant differences in all domains of social support among the students of different grade,familial income,and nationalities(P<0.05 for all) except for objective social support in the students of different nationalities(P>0.05).The scores of all social support domains were significantly different among the students of whether being a singleton and a student leader(P<0.05) except for the score of objective social support(P>0.05).There were significant differences in the scores of subjective social support and support utilization among the students with different personality(P<0.05).Correlation analyses showed that the score of depressive symptoms was reversely correlated with the scores of overall social support(r=-0.153,P<0.001),objective support(r=-0.055,P<0.001),subjective support(r=-0.358,P<0.001),and the utilization of support(r=-0.305,P<0.001)Conclusion Depressive symptoms should be concerned among high school students in Yunnan province and strong social support could promote mental health of high school students.