With the leaves of pink and green Davidia involucrata in Gongxian as test materials, we measured the physiological indexes including the pigment, osmotic regulator and related enzymes, and analyzed the correlation. In order to provide the theoretical basis and technical reference for the breeding and rational cultivation of pink D. involucrata, the study investigated the key factors affecting the coloration of D. involucrata from physiological characteristics. The results showed: (1) the content of anthocyanin in pink plants was extremely significantly higher than that of green plants in spring, summer and autumn. Its content reaches its lowest in summer. The total content of chlorophyll of pink plants were extremely significantly lower than that of green plants in summer and autumn. The difference of carotenoid and flavonoid content was no significant, and their yearly changes were stable. (2) There was also no significant difference in soluble sugar and soluble protein content, its content reaches its lowest in summer. The proline content of the pink was significantly higher, slowly increasing with the seasonal change. (3) The activities of phenylalanine ammonialyase (PAL), chalone isomerase (CHI), and superoxide dismutase (SOD) of pink plants were significantly higher than that of green plants. PAL, CHI and SOD played the role of decomposing chlorophyll and promoting anthocyanin synthesis, while the effect of peroxidase (POD) was opposite. The activity of PAL in two plants firstly weakened and then increased with the seasonal change, while the activities of POD and SOD were opposite. The activity of CHI of pinkcolor plants gradually decreased, and the green ones increased and then decreased. (4) Anthocyanin was negatively correlated with chlorophyll, flavonoids, soluble proteins, CHI, SOD and PAL. In conclusion anthocyanin was the determining factor of leaf color change. CHI, SOD and POD were the main enzymes that regulated anthocyanin degradation rate.