The objective of this study was to characterize plant adaptation to the morphostructure of rock in karst areas. Selecting seven types of woody communities growing on three rock types (limestone, dolomite rock, dolomitic sandstone) as test objects, the fractal dimension and spatial syntax were adopted to study the morphostructure of cracks and pores of the rock structural plane, and its correlations with the characteristics of plant communities. Results indicated that the lacunarity index of cracks and pores of the limestone structural plane was the largest, that of dolomite was intermediate, and that of dolomitic sandstone was the smallest. The fractal dimension showed the opposite trend to that of the lacunarity index. With respect to the integration degree, control value, and density value of cracks and pores, the rocky structural plane of dolomitic sandstone was ranked as the largest, followed by that of dolomite, while that of limestone was the smallest. The species diversity and the carbon and nitrogen content of the dominant species in dolomite habitat were the highest, followed by those in the dolomitic sandstone habitat, while these were the lowest in the limestone habitat. The index of fractal dimension had a significant correlation with the index of spatial syntax, both of which could reveal the rock morphostructure well. In general, the species diversity index and the carbon and nitrogen content of the dominant species had a strong correlation with the fractal dimension index and the spatial syntax. Provided that the growing environment is similar, the rock morphosturcture of dolomite was the most suitable for plant growth, followed by that of dolomitic sandstone. However, the rock morphostructure of limestone was comparatively unfit for plant growth. It is necessary to study the rock morphostructure in karst areas for vegetation restoration in these areas.