To explore the existence of natural foci on Marmota himalayana plague in Sichuan province and to provide basis for prevention and control of the disease.Both epidemiological investigation and laboratory tests were used to provide the host animal and fleas of the vectors with Yersinia pestis carriers.30 species of animals were found to belong to 10 orders. Ochotona curzoniae and M. himalayana were the most common ones while 7 species of the fleas belonged to 7 genera and 3 families. M. himalayana was the main reservoirs while Callopsylla dolabris and Oropsylla silantiewi served as vectors. The 13 Y. pestis were identified from 43 Marmota samples. 8 samples were identified under IHA, with the highest titer of herding-dogs serum as 1:10,240. 19 samples were F1 antigen positive using RIHA and the highest titer of M. himalayana serum was 1:409,600. The major foci was 4545 km2, distributed at Dege county in Sichuan province.We have confirmed the existence of natural foci on M. himalayana plague in Sichuan province.