Abstract: The development of fractal theory and its applicati on in ecology is reviewed in the paper, following with the analysis of horizonta l two-dimension spatial pattern of concentration field of algea chlorophyll-a in Meiziya Reservoir. Thro After the comparison and analysis of spstaial occu pancy potential of various concentration contours in different time, The authors determine that the concentration is of steady presence which can decide phytopla nkton's growth and change potential.