Abstract: We investigated the changes of plant functional traits and their relationships with environmental factors during the succession process by using generalized linear model, RLQ analysis and fourth-corner analysis in Xishuangbanna tropical forests at different successional stages after slash-and-burn cultivation. The results showed that there were significant differences in the distribution characteristics of functional traits between secondary and primary forests, while the differences between secondary forests were not significant. Among them, leaf traits changed from a conservative strategy to an acquisition strategy, and seed weight and wood density changed from an acquisition strategy to a conservative strategy. The association of single traits with specific environmental factors increased with succession, functional traits in early succession were strongly associated with soil pH only, while functional traits in middle succession and primary forests were strongly associated with multiple environmental factors, with primary forests being most significantly influenced by total soil phosphorus.