Snow leopard (Panthera uncia) is the flagship species of biodiversity conservation on the Qinghai-Tibet plateau. They feed mainly on Bharal (Pseudois nayaur). Study of the habitat suitabilities of the two species can provide a scientific basis for their population protection in Sanjiangyuan National Park. Based on our extensive survey of Pseudois nayaur and Panthera uncia distributions in the national park, we used a Maximum Entropy (MaxEnt) model to evaluate Pseudois nayaur and Panthera uncia habitat suitabilities and their spatial distribution patterns in the food chain, and to investigate the relationship between habitat and the main environmental variables. The results showed that altitude, the precipitation during the driest month, and the annual temperature range were the main environmental factors affecting the spatial distributions of Pseudois nayaur and Panthera uncia. The optimum altitude ranges of the two overlapped in the range of 4660 ~4730 m, and the precipitation during the driest month and the annual temperature range of the two overlapped in the range of 2 ~4 mm and 33.7℃~37.0℃, respectively. The areas of high- and medium-level suitable habitat for Panthera uncia and Pseudois nayaur in the national park were 19 246 km² and 39 977 km², accounting for 15.63% and 32.47% of the total area of the park, respectively. Meanwhile, the areas of overlap for high- and medium-level suitable habitat was 16 621 km², accounting for 13.50% of the total area of the park. These were mainly located in the northeast, central and eastern regions of

Lancang river source park and the southeast region of Yangtze river source park. This study can provide a theoretical basis for the formulation of protection and management measures for Pseudois nayaur and Panthera uncia in the Three-River-Source National Park.