Przewalski's Gazelle (Procapra przewalskii) is endemic to China and was classified as Critically Endangered by the International Union for Conservation of Nature (IUCN) in 1996. Once widespread, it has declined to 8 populations near Qinghai Lake. Subjected to the dual pressures of human activities and natural enemies, the gazelle is faced with the probability of extinction. By analyzing past years' statistical data, a Population Viability Model of Przewalski's Gazelle (PVMPG) was established. STELLA, a graphical-interface software, was used, first to establish the PVMPG model, and then to simulate environmental conditions and predict the future population viability. Finally, VORTEX software was used to forecast the probability of extinction of Przewalski's Gazelle in 100 years, to verify the reliability and rationality of the PVMPG model that was developed using STELLA. The results will provide the theoretical basis for the Przewalski's Gazelle population's protection.