Differences in genetic characteristics and the external environmental conditions jointly determine the expression of plant functional traits, which can reflect the adaptation strategies of species to environmental conditions. The functional traits of Phragmites australis ramet and leaf in four habitats (Saline-alkali habitats, Xeric habitats, Wet habitats, and Aquatic habitats) in Zhalong wetland were studied by large sample sampling and statistical analysis. The differentiation law of functional traits of P. australis in different habitats and its response to soil factors were analyzed. The results showed that:(1) the functional traits of P. australis in different habitats showed moderate variation. The ramet and leaf traits were the lowest in saline-alkali habitat (P<0.05), and the ramet and leaf traits except leaf area and specific leaf area were the highest in aquatic habitat. The variation coefficients of plant height and plant weight were 15.96%-48.61% and 38.65%-87.82% within populations, and 46.58% and 66.39% among populations. The variation coefficients of leaf traits within populations ranged from 13.21% to 72.37%, and between populations ranged from 26.46% to 57.03%. (2) There were synergistic changes in functional traits of P. australis in different habitats. The plant height, plant weight, leaf length, leaf width, leaf area, and single leaf weight were positively correlated (P<0.01), and the correlation between specific leaf area and other traits varied with different habitats. (3) In situ soil factors of P. australis in different habitats showed heterogeneity. The variation in functional traits of P. australis were the result of the combined effects of moisture, pH, organic matter, and available nitrogen, among which moisture, organic matter, and available nitrogen were positively driven, while pH was negatively driven. Therefore, P. australis could better adapt to different living environments through self-regulating functional traits, and soil factors in different habitats at local scale were the main factors leading to the differentiation of functional traits of P. australis.