Kozlov's Pika, Ochotona koslowi is a rare endangered and the most ancestral lagomorph species in Ochotona genus. Little is known about the survival status as well as the biological characteristics of this species since it was named in 1894. In this study,we studied its feeding habits by analyzing the contents of gastric and colon collected from 13 individuals and 60 feces samples from the trapping regions in Northern Tibet during October and November,2007.A total of 15 plant species were identified,belonging to 6 distinct families including Leguminosae,Chenopodiaceae,Cyperaceae, Gramineae, Cruciferae and Compositae that constituted 39.44%, 36.00%, 16.42%, 3.75%, 2.67% and 1.25% of all recognizable plant tissue debris,respectively.Leguminous plants were preferred by Kozlov's Pika.