Abstract: The capability of the new generation dynamic vegetation model CLM5-FATES (Community Land Model version 5 - Functionally Assembled Terrestrial Ecosystem Simulator) for the distribution of mixed needleleaf and broadleaf forest in the Changbai Mountains urgently needs to be evaluated, which is of great significance for the development of the new generation of models. Based on the maximum carboxylation rate at 25 ℃, specific leaf area, and leaf longevity, this paper first explores the parameter sensitivity of the distribution of mixed needleleaf and broadleaf forest in the Changbai Mountains in the CLM5-FATES model, and then investigates the model’s ability to simulate the distribution of these forests. The study finds that different combinations of trait parameters significantly affect the distribution of vegetation types in the region. The maximum carboxylation rate at 25 ℃ and specific leaf area have a greater impact compared to leaf longevity. Under an appropriate combination of trait parameters, the CLM5-FATES model can reproduce the observed distribution of mixed needleleaf and broadleaf forest in the Changbai Mountains. This study validates the applicability of the model to the mixed needleleaf and broadleaf forest in the Changbai Mountains, providing crucial support for further research on climate-vegetation interactions.