Objective  To explore the prevalence and influencing factors of anxiety emotion among Chinese adolescents during a major public health emergency (PHE) for providing evidence to the development of appropriate intervention strategies.

  Methods  An online self-administered survey via Sojump platform was conducted among 208 433 adolescents (16 – 22 years old) in 34 provincial level administrative divisions across China during March 2020. A self-designed questionnaire and Generalized Anxiety Disorder-7 (GAD-7) were adopted in the study.

  Results  Among the 170 830 participants with valid responses, 40 448 (23.7%) were identified as having anxiety emotion during the major PHE; of the participants with anxiety emotion, 80.2% (32 458), 14.5% (5 878), and 5.3% (2 152) were assessed as having mild, moderate, and severe anxiety, respectively. Unconditional multivariate logistic regression analysis revealed following risk factors for having anxiety emotion during the major PHE among the adolescents: female gender, living in a region affected by an ongoing major PHE with more than 100 reported cases, with trauma history, and being affected directly or indirectly by the major PHE but not being a confirmed disease case; whereas, having a fair or good relationship with family members and usually with a general or stable emotion before the major PHE were protective factors against anxiety emotion during the PHE.

  Conclusion  During the period of a major PHE among Chinese adolescents, the prevalence of anxiety emotion was relatively low and mainly affected by gender, the number of confirmed disease cases within a residential area, relationship with family members, trauma history, and impact severity of the major PHE.