The issue applied the fractal theory to study the character of dominant macrophytes' leaves in Baoan Lake of Hubei province. The leaves are the most representative modules, and many scientists study the morphology of them. The leaves of macrophytes are the main organs that participate the photosynthesis in the water. The leaf numbers, the leaf surface and spatial pattern of them directly influence the illumination intensity and spectrum component, which affects the plant' s utilization efficiency of light. By introducing the Box-counting dimension ( self-made software), one method the fractal theory provided, the scanned photos of leaves were treated. The fractal dimension ( FD) of Potamogeton malaianus leaves was between 1.322 and 1.520, with an average of 1.441, and a standard deviation of 0.0547. The FD of Potamogeton crispus leaves was between 1.381 and 1.565, with an average of 1..472,and a standard deviation of 0.0489. The FD of Najas marina leaves was between 1.209 and 1.406, with an average of I. 325, and a standard deviation of 0.0547. The FD of Hydrilla verticillata leaves was between I. 001 and 1.217, with an average of I. 103, and a standard deviation of 0.0456. The FD of Ceratophyllum oryzetorum leaves was between 1.221 and 1.542, with an average of 1.442, and a standard deviation of 0.0862. By compared with the morphological differences among their leaves, we can well realize the ecological meanings of the fractal dimensions ( FD) calculated. The sequence of average FD of leaves was: Potamogeton crispus > Ceratophyllum oryzetorum > Potamogeton malaianus > Najas marina > Hydrilla verticillata, which indicated the difference in the ability of spatial occupying and utilizing among different species' leaves. The t-test for fractal dimension of 5 macrophytes' leaves showed that there are no significant differences between Potamogeton crispus, Ceratophyllum oryzetorum arid Potamogeton malaianus, which could be caused by the reason Potamogeton crispus arid Potamogeton malaianus belonging to Potamogetonaceae. The t-test also showed that the leaves of Ceratophyllum oryzetorum have a spatial pattern more similar to them. The work well describes the morphology of different species' leaves in quantity. It will benefit realization of the macrophytes' adaption to water body, arid provide the basic information for our further study Oil the macrophytes pattern at large scale.