In the ecologically vulnerable area which locates in northwest arid and semiarid areas, ecological land is the important guarantee to maintain the security and stability of regional ecological environment. Studying the simulation of ecological land use change is of great significance. Accordingly, based on the typical ecologically vulnerable area—Dengkou County, this paper simulates ecological land use evolution of Dengkou County, using the four remote sensing image interpretation data of 2002, 2007, 2012 and 2015. Taking ecological ecoresistance barriers and EnKF-MCRP model into account, an ecological resistance surface was built. The EnKF-MCRP model was constructed to simulate the evolution of ecological sources considering the ecological sources change, ecological source level, distance and base surface resistance characteristics. The results showed that the combination of data assimilation and EnKF-CA/Markov model made a total accuracy of 82.4%, by using ensemble Kalman filter, the model can accumulate less errors and improve the accuracy of simulation, i.e., data assimilation can reduce the accumulation of errors. According to the expandability, ecological sources of Dengkou County were divided into five grades, of which the spatial layout of 3, 4, 5 grades formed the northeastsouthwest and northwestsouthwest pattern of desertification prevention. The building of EnKF-MCRP which takes the ecological source evolution into consideration made the highest precision. And the area of ecological sources and spatial distribution were the closest to the reality, of which the variance met 0.4. Different levels of ecological sources and ecological barriers were used to modify the model, which can improve the accuracy of the simulation results. This study could provide a scientific basis for the current and future ecological land planning and management.