Abstract: Mangrove ecosystem is an important coastal blue carbon ecosystem. To reveal the variation and dimensional correlation of leaf functional traits of young mangrove plantation can help us understand the adaptation mechanism of young mangrove to changing environment and its community assembly rules. A total of 9 932 leaves were collected from 764 plant individuals in the mangrove restoration area of Anle Village, Xichang Town, Beihai City, and leaf thickness, leaf area, leaf volume, specific leaf area, leaf dry matter content, and leaf tissue density of each leaf were measured. The variation sources and correlations of leaf functional traits at leaf, individual, and species scales were explored using generalized linear models, varcomp function, principal component analysis, and pearson correlation analysis. The results showed that the coefficient of variation of leaf functional traits was the largest at leaf scale and the smallest at species scale. The variation of all leaf functional traits mainly came from species scale. the first two principal component axes explained 75.6%, 72.8% and 96.8% of the total variance of the 6 functional traits, respectively. The results showed that the variation coefficient of the six leaf functional traits was highest at the leaf scale and lowest at the species scale. The variation of leaf thickness, leaf area, leaf volume, specific leaf area, leaf dry matter content, and leaf tissue density mainly originated from species scale. Principal component analysis results showed at the leaf, individual and species scales, the first two principal component axes explained 75.6%, 72.8% and 96.8% of the total variance of the six functional traits, respectively. At the three scales, there leaf thickness, leaf area, and leaf volume were significantly positive correlated, while specific leaf area, leaf dry matter content, and leaf tissue density were mainly negatively correlated with other traits.