Growing network approach analyses of posttraumatic stress disorder (PTSD) have enhanced the knowledge of PTSD symptomatology. This study aims to explore changes in network patterns of PTSD symptoms among youth survivors following the Zhouqu debris flow through a network approach. A two-year longitudinal study was conducted to follow 1460 children and adolescents at 3, 15, and 27 months after the disaster. Symptoms with high centrality varied at different time points. Sleep problems and nightmares exhibited high centrality at 3 months, and their centrality decreased over time, while the centrality of physiological cue reactivity and flashbacks increased over time and reached a high level at 27 months. The global connectivity of the network was stronger at 27 months than at 3 and 15 months. These findings provide novel insights into youths' PTSD symptom evolution. Temporal differences in PTSD symptoms merit more attention from researchers. Different core symptoms in acute and chronic PTSD structures should be treated as targets at different stages following trauma in clinical practice.