Objective:To learn about the epidemic law of animal plague in natural plague focus of Himalayan Marmot in Yumen City of Gansu Province, to explore the epidemiological characteristics of plague in the area and to provide scientific basis for formulating prevention and control strategies of the plague. Methods:The animal plague surveillance data of natural plague focus of Himalayan Marmot in Yumen City, Gansu Province from 2014 to 2021 were collected, main host density, rate of infected with fleas, flea index, small rodent species, bacteriology, serology were studied. Excel 2007 software was used to analyze the plague epidemic situation in the focus. Results:From 2014 to 2021, the total average density was 0.06 per hm 2 of the marmots. A total of 19 300 traps were placed, and 209 rats were caught, with an average catch rate of 1.08%. Among them, Dipus sagitta (59.81%, 125/209) and Mongolian Five-toed Jerboa(31.10%, 65/209) were dominant small rodent species. Totally 877 marmots were checked, 184 with flea. The rate of infected with fleas of marmots was 20.98%, with a flea index of 1.00, Callopsylla dolabris (52.69%, 461/875) and Oropsylla silantiewi (47.20%, 413/875) were dominant species in vector. The rate of infected with fleas of burrow was 7.72% (173/2 241), with a flea index of 0.20. A total of 39 strains of Yersinia pestis were isolated from infected animals. Among them, 35 strains from the marmots, and 4 strains from vectors. Totally 913 serum samples were checked from marmots and shepherd dog, the positive serum was 34. Among them, the positive rate of shepherd dog was 13.98% (33/236). Conclusions:The plague epidemic situation in natural plague focus of Himalayan Marmot in Yumen City of Gansu Province is still serious. The monitoring of plague should be strengthened, and the comprehensive measures for prevention and control of the plague should be carried out to prevent a outbreak of the plague in human being.