Objective To explore the relationship between social support,diabetes-related negative emotions and self-management in adolescents with type 1 diabetes mellitus(T1DM),and analyze the mediating effect of diabetes-related negative emotions on social support and self-management.Methods Used the convenient sampling method,208 patients with T1DM who were 13 to 18 years old in the outpatient department of children's endocrinology of a third grade A children's hospital in a city from April 2019 to December 2022 were investigated with the Adolescent Social Support Scale,the Diabetes Problem Scale,and the Adolescent T1DM Self-Management Scale.Results The scores of social support and self-management of adolescents with T1DM were 58.00(49.00,68.00)and 78.50(61.00,91.00),respectively.The score of diabetes-related negative emotions was(47.14±21.59).There was a positive correlation between social support and self-management(r=0.630,P<0.01),and a negative correlation between diabetes-related negative emotions(r=-0.688,P<0.01)and social support and self-management(r=-0.753,P<0.01).The mediating effect of diabetes-related negative emotions on social support and self-management accounted for 66.25%.Conclusion Negative emotions of diabetes play a part of mediating role between social support and self-management.Medical workers,parents,and educational worker should pay attention to patients'diabetes-related negative emotions,and give corresponding social support and intervention in time,so as to improve their negative emotions and improve their ability of disease self-management.