Based on the spatial ecology theory and the index of landscape pattern,in this paper,the landscape types of a desert–oasis ecological system was dominated by the run off of rivers．The method of spatial grid and obtaining landscape information from the gril cells was put forward and was used to analyze the landscape pattern of the lower reach of Heihe River basin as an example．The analysis results indicate that compared with the land use type analysis method the landscape cheracteristics affected by run off could be indicated and the landscape type was consistent with the ecological pattern of the desert–oasis using the method put in this paper．