Abstract: The horizontal patterns of the endangered species, Adenophora lobophylla and the widespread species, A. potaninii populations at different altitudes have been studied by the Box Dimensions of Fractal Theory. The Box Dimensions of the horizontal distribution patterns of A. lobophylla and A. potaninii populations was direct rate to the ability for A. lobophylla and A. potaninii populations to occupy the space in the communities and which is closely related to the environmental factors. At altitude 2700～3100m,where there are the better environmental conditions for A. lobophylla and A. potaninii populations to live, the Box Dimensions of both species reached the highest value. Below altitude 2700m or above altitude 3100m,because the harsh environmental condition, the ability for both species to occupy space become weaker. At different altitudes, the ability for A. potaninii population to occupy space in the communities was always stronger than that of A. lobophylla populations. Below altitude 2700m,the Box Dimensions of A. potaninii populations were 4.5 times as higher as that of A. lobophylla populations. At altitude 2700~ 3100m, where there was the better environmental conditions for both A. lobophylla and A. potaninii populations to live, the Box Dimensions of A. potaninii was 1.5 times as higher as that of A. lobophylla population. Above altitude 3100m,the Box Dimension of A. potaninii populations was 1.8 times as higher as that of A. lobophylla population. It is reasonable for us to believe that the intrinsic adaptation, competition of A. lobophylla populations were weaker than that of A. potaninii population.