[Objectives] Small populations are isolated or heterogeneous populations with survival risks under the influence of natural factors or anthropogenic activities, and understanding their formation are the basis to formulate conservation strategy and rescue programme. The Giant Panda (Ailuropoda melanoleuca) has many small populations which are isolated from each other, and the living conditions of the small populations will determine the overall conservation effectiveness of the species. [Methods] Taking the Giant Panda population in Duoer Reserve of Gansu Province as an example (Fig. 1), based on the investigation of population distribution, space utilization and disturbance status of the Giant Panda in the reserve, the habitat suitability assessment was completed, and the spatial and temporal pattern of effective utilization of the Giant Panda and its environmental capacity are also analyzed (Table 1). [Results] The results showed that: (1) The suitable habitat area of the reserve is 5 789.2 hm2, and the sub-suitable habitat area is 18 165.6 hm2, accounting for 43.9% of the total area of the reserve (Table 2). The high-quality habitat is mainly distributed in Gongbulong area, which is the main distribution area of Giant Pandas in the reserve (Fig. 2). (2) Grazing is the main disturbance factor of Giant Panda habitat in the Gongbulong area, and the pasture occupies 43.7% of this area. The total area of suitable and sub-suitable habitats in the Gongbulong area decreased by 1 200.9 hm2 under grazing interference, accounting for a decrease of 12.9% in the total area of the region (Fig. 3, Table 3); moreover, the fragmentation of habitat got worse. (3) Pasture inserted into Giant Panda habitat and shaped mosaic pattern with habitat, it also led to the isolation of suitable habitat. Due to the seasonal features for grazing, Giant Pandas were forced to choose seasonal migration along altitude retrograde to avoid the interference, which resulted in a suitable habitat area of 364.0 hm2 available for their use, sub-suitable habitat area is 1 088.9 hm2 in summer, and the available suitable habitats are 756.4 hm2 and the sub-suitable habitat area is 1 719.2 hm2 in winter and spring (Table 4). [Conclusion] Studies have shown that the spatial pattern of pastures and grazing activities lead to insufficiency of living space and habitat isolation for Giant Pandas. Especially in summer, the minimum environmental capacity is only 2 to 3, which cannot guarantee the long-term survival of large populations. It also affects their life history and population fitness resulting in a low encounter rate in field. It is suggested to optimize the functional zoning, adjust the pasture layout, control the grazing activities to reduce the disturbance and increase the habitat supply, and implement Ex-situ conservation programme to improve the habitat environment and living conditions of the small population.