From March to July, 2010 and 2011, the nest structure and nest-site selection of Upland Buzzard (Buteo hemilasius) were investigated on the west bank of Dalai Lake in Dalai Lake Natural Reserve,Inner Mongolia. Field observation found that the earliest activity of Upland Buzzard appeared on around March 25;egg-laying began in the middle and late April and the breeding ended at about the beginning of July. By the direct observation and plot sampling method in the field,we positioned thirteen nests, measured twenty ecological factors of this thirteen samples. The Cluster Analysis based on the Euclidean distance was used to assess all twenty ecological factors. Through a rough measurement, the Upland Buzzard's nest is characterized in that-the outer diameter is (94.7±4.2)cm while the inner diameter (24.8±1.5)cm; nest deep is (14.0±0.9)cm and nest height is (46.1±2.7)cm.The results of ecological factors analysis indicated that in West bank of Dalai Lake,Upland Buzzard's nests are mainly centralized distributed in the lake bank or blisters near the cliff;nesting sites are mainly middle or higher slope position;the gradient ranged from 15°-45° on sunny slopes and semi-sunny slopes;the nest-sites have high-level concealment, the density of herbaceous is higher than 5 strains/m²;average high of vegetation is higher than 30cm; distance of nests to cliff upper is between 2-5 m; the distance to water resource is within 100m; distance to settlements is more than 1 km;distance to the prairie path is more than 0.5km while has no special requirements of species richness. The principal components analysis shows that there are three most important factors of Upland Buzzard nest-site selection as follows, the covert factors (including nest-site area plant characteristics and topographic features), human interference factors and food factors. In the main compositions, Vegetation coverage, distance to settlements,nest height and distance to prairie paths have the highest relative coefficient absolute value.