This study was designed to investigate the roles of numbing of positive and negative emotions in PTSD symptomology and related functional impairments. 14,465 Chinese children and adolescents who personally experienced the 2008 Wenchuan earthquake (in Sichuan province, China) took part in the study. Emotional numbing and other PTSD symptoms were assessed by the University of California-Los Angeles PTSD Reaction Index for Children. Functional impairment was measured by the Pediatric Quality of Life Inventory 4.0 Generic Core Scales. Item response theory (IRT) analysis showed that both numbing of positive and negative emotions demonstrated acceptable item response characteristics; numbing of positive emotions had better discrimination. Group comparisons revealed that participants who reported numbing of both positive and negative emotions had the highest risk of developing PTSD, most severe PTSD symptoms and functional impairments, with large effect sizes when compared with participants with no emotional numbing symptoms. Reporting only numbing of positive emotions had moderate effects, and reporting only numbing of negative emotions had smaller effects. The results revealed associations between emotional numbing patterns, posttraumatic stress symptoms and impairments in quality of life, and suggests that additional research is needed to explore generalized emotional numbing in children and adolescents in future PTSD research.