Abstract: The diversity of phenotypic characters of Myricaria laxiflora and its patterns, as well as the divergence of characters and its relationship with habitats were studied in this paper, using 11 anatomical parameters of stem as phenotypic characters and partially sampling the populations covering whole distribution area of the species. The results indicated that each character among populations and general characters in various populations have significant or extremely significant differences. 63% divergences of characters belong to inner-population variation, while 37% belong to geographical variation. The character variation measure in populations correspond to that of the environment. The 5 pre-populations above Fengjie, Sichuan Province are more similar with each other, while the 5 post-populations from Fengjie are otherwise, which showed that the diversity center of phenotypic characters is located in the valley between Three Gorges rather than the valley beyond them.