Feeding site selection of Marco polo sheep in Taxkorgan Nature Reserve was investigated in June to August in 2016 and 2017. Totally, 46 plots of feeding sites and 46 plots of control sites were measured. And the effects of 12 ecological factors on feeding site selection of Marco polo sheep were evaluated, including aspect, slope position, slope, altitude, vegetation coverage, shrub species richness, graminoid species richness, forb species richness, plant density, aboveground biomass, distance to water and distance to disturbance. The results of comparison between feeding sites and control sites showed that only slope, altitude and distance to water from 12 ecological factors have no significant difference (Table 1), and Marco polo sheep have strong preference on these 12 ecological factors when select their summer feeding sites studied by Vanderploeg and Scavia selection index (Table 2). The summer feeding resource selection function of Marco Polo sheep is Y(X) = e (26.145﹣0.008A + 15.102V + 0.653F + 0.001D), indicating that vegetation coverage (V), forb species richness (F), altitude (A) and distance to disturbance (D) are the 4 key ecological factors that affect the feeding sites selection of Marco polo sheep (Table 4). Analyzed by receiver operating characteristic (ROC) curve (Fig. 1), accuracy of this function was 94.38%, which can well reflect the summer feeding sites selection of Marco Polo sheep.