Background: To investigate the present scenario of postoperative kinesiophobia in adolescents with pectus excavatum, analyze the influencing factors, and determine the path of action among the factors to provide a reference for intervention in clinical settings. Methods: Using purposive sampling, we selected 212 adolescents with pectus excavatum who were treated at the Department of Pediatric Thoracic Surgery of Guizhou Provincial People’s Hospital and Shanghai Children’s Medical Center Guizhou Hospital between September 2022 and December 2024. The following scales were used: General Information Questionnaire, Numerical Rating Scale for Pain, Tampa Rating Scale for Kinesiophobia, Pain Catastrophizing Scale, Chinese Version of General Self-Efficacy Scale, and Chinese Version of Patient-Reported Outcome Measurement Information System Physical Functioning Short-Form 6b. A generalized linear model was used to identify the influencing factors, followed by path analysis. Results: Kinesiophobia was observed in 83.5% of adolescents following surgery for pectus excavatum.Furthermore, the incidence of moderate to severe pain was 71.2%, and the positive rate of pain catastrophizing was 65.1%.We identified the degree of chest wall deformity , pain catastrophizing, pain degree, and self-efficacy as the factors influencing postoperative kinesiophobia in adolescent children with pectus excavatum. Path analysis revealed that the degree of chest wall deformity directly influenced the degree of pain and physical function. Conclusions: The incidence of postoperative kinesiophobia is high in adolescent children with pectus excavatum. Medical staff should pay attention to postoperative kinesiophobia in children, decrease children’s fear of early postoperative activities from the perspective of controlling pain catastrophizing, and help in reducing pain and improving physical function and self-efficacy .