Taking Wengniute Banner of Chifeng City, Inner Mongolia as a research area, the landscape pattern index with different granularities was calculated, and 3200m was identified as the optimal granularity based on granularity inverse method and principal component analysis. According to the optimal granular landscape features, totally 51 ecological sources were selected. Combined with the regional characteristics, the ecological resistance surface was constructed, and 49 potential ecological corridors and 58 ecological nodes were extracted. Then, the density analysis of corridors and nodes was carried out. The results showed that there were significant differences in the ecological conditions of Wengniute Banner between the east and the west. The mid-low-mountain hilly areas in the west included three high-node-density areas, which need to be protected and constructed, and the source areas and corridors were concentrated. The sand plains in the eastern plain were widely distributed, and the source areas and corridors were scattered. The energy circulation mainly depended on the Silam River and Laoha River, and the ecological structure was poorly connected. Taking landscape connectivity and scale effects into consideration, the ecological sources were extracted based on the optimal granularity, which was more scientific and objective than traditional methods. The results would provide an objective and effective basis for regional landscape pattern optimization.