ObjectiveThis study used network analysis to investigate the cross-sectional and longitudinal network between PTSD symptoms within mother-adolescent dyads at 12 and 18 months after the 2008 Wenchuan earthquake. MethodsThe sample was from the Wenchuan Earthquake Adolescent Health Cohort. 399 mother-adolescent dyads completed the Posttraumatic Stress Disorder Self-Rating Scale at 12 and 18 months after the earthquake. We assessed central symptoms (those with the most significant influence on other symptoms) and bridge symptoms (symptoms connecting different communities) in contemporary networks (i.e., cross-sectional networks). Subsequently, cross-lagged panel network analyses (CLPN) were performed to estimate longitudinal relationships among symptoms between dyads. ResultsIn the contemporary networks, symptoms such as “intrusive thoughts” of both dyads and “flashbacks” of adolescents were central, indicating that they are crucial in maintaining the network of PTSD symptoms. Additional symptoms such as maternal “difficulty in concentration” and dyads’ “pessimism and disappointment” should also be considered because of their central roles. Moreover, the temporary network did not directly replicate the contemporary networks, with adolescents’ “nightmares” at 12 months having a high influence on other PTSD symptoms at 18 months. LimitationsSelf-reported tools other than clinical diagnoses were used to collect data. ConclusionsThese symptom-level associations at cross-sectional and longitudinal networks extend our understanding of PTSD symptoms among mother-adolescent dyads by pointing to specific key symptoms of PTSD that may drive the co-occurrence of PTSD among dyads. Recognizing these symptoms is imperative for the development of targeted interventions and treatments aimed at addressing comorbid PTSD in mother-adolescent dyads.