Abstract: This study investigated the relationship between phenotypic differences in leaf color and physiological factors influencing color expression in different leaf positions of Syzygium album Q. F. Zheng. To achieve this, S. album specimens at the same growth and developmental stage were selected for analysis. The study assessed leaf color using the Royal Horticultural Society Colour Chart (RHSCC), recorded color difference parameters, and measured pH and electrical conductivity (EC) values. In addition, pigment composition and soluble sugar content were quantified to examine their contributions to leaf coloration. Results revealed that: (1) Leaf color varied significantly across different positions, transitioning from red to yellow-green to green, with a gradual decrease in redness (+a*) and a gradual increase in green (-a*) and yellow (+b*). Leaf brightness (L*) exhibited a highly significant positive correlation with both the Chla/b and Fla/Chl ratios (P<0.01) and a negative correlation with soluble sugar content (P<0.05). (2) Leaf red-green coloration (a*) was significantly positively correlated with leaf fluid EC, anthocyanin content, and the OPC/Fla ratio, but significantly negatively correlated with leaf fluid pH, chlorophyll, carotenoid, and flavonoid content. Leaf coloration (C*) was significantly negatively correlated with soluble sugar content. (3) Leaf color differences were not determined by a single plastid pigment but rather by the relative composition and ratio of multiple pigments. The combined analysis of color difference parameters and pigment ratio coefficients facilitated the reduction of perceptual errors in assessing leaf color phenotypes through data mining approaches. These findings provide a theoretical foundation for evaluating color difference parameters and elucidating the physiological mechanisms underlying color expression in colored-leaf tree species.