Food habit of small mammals is an important component in the study of population ecology. In this study, gastric contents and colon contents of 12 plateau pikas（Ochotona curzoniae）were tested through microhistological analysis in The Haibei Resrarch Station of Alpine Meadow Ecosystem under Chinese Academy of Sciences during July to June, 2018. The results showed that a total of 16 species（genus）of plants from 7 different families were identified in the gastric contents, including 15.07% of Elymus nutans, 9.07% of Oxytropis spp., 7.38% of Kobresia spp., 7.11% of Potentilla anserine. In contrast, only 6 species（genus）of plants from 3 different families were identified in the colon contents, including 21.99% Kobresia spp., 13.68% of Elymus nutans, 5.04% of Poa spp., 2.00% of Potentilla anserine. According to the microhistological results of contents of gastric and colon, through analyzing Simpson diversity index, Shannon-Wiener diversity index, Pielou evenness index and niche width index of the food composition of plateau pikas, it shows that Simpson diversity index, Shannon diversity index and niche width index were higher in gastric contents than in colon contents, however, Pielou evenness index was not. The recognizable rate in gastric contents was significant higher than in colon contents（χ ²=8.619，df=1，P<0.01）. The results indicated that the contents of gastric and colon observed in food habit were obviously different from each, the food preference indices were different, microhistological analysis of gastric contents can more accurately responds food composition and food selectivity of plateau pikas than colon contents.