ABSTRACT The outbreak of coronavirus disease 2019 (COVID-19) has brought a series of psychological shocks to adolescents, it may cause psychological security problems. The purpose of this study was to explore the influence of social support on psychological security of adolescents and the role of emotional regulation and the experience of COVID-19 infection. 615 ( 14.64 ± 1.29) randomly selected Chinese adolescents were tested with the Perceived Social Support Scale (PSSS), Emotion Regulation Questionnaire (ERQ), and Psychological Security Questionnaire (PSQ). Structural equation modelling results show that: (1) Social support positively predicted psychological security; (2) Social support positively predicted cognitive reappraisal, and cognitive reappraisal positively predicted psychological security. At the same time, cognitive reappraisal played a mediating role in the relationship between social support and psychological security; (3) Social support negatively predicted expressive suppression, and expressive suppression negatively predicted psychological security. Meanwhile, expressive suppression played a mediating role in the relationship between social support and psychological security; (4) COVID-19 infection experience positively moderates the relationship between expression inhibition and psychological safety. This study provides theoretical experience reference for the solution of adolescent psychological problems in crisis situation.