The wolf (Canis lupus) is currently decreasing and its natural habitat was heavily disturbed by nature and human activities at Dalai Lake Natural Reserve in Inner Mongolia of China. To characterize the wolf′s habitat, habitat selection was investigated from October to December 2008 at Dalai Lake Natural Reserve in Inner Mongolia. Eleven ecological factors were used to define the habitat in each of 20 m×20 m plots of 59 samples. They are the concealment level, the snow depth, the distance to water resource, the habitat type, the vegetation type, the vegetation height, the distance to settlements, the distance to grass road, the distance to pasture and the distance to fence. The Cluster Analysis based on the Euclidean distance and the distribution frequency statistics were used to assess all eleven ecological factors in 59 samples. The result indicated that the habitat of wolf shared the following characteristics: habitat with the high-level concealment, the distance to water resource within 100m, habitat with wide field and high grass, dry reed pond and bend of a river, swamp vegetation mainly including the reed and the willow shrub, food richness, far away from settlements (more than 1000m away), far away from grass road (at least 1000m), close to pasture (less than 500m). The Principle Component Analysis was performed to simplify the system of variables. Five components were identified, which explained 81.183% of total variance. Component I explained most of the variance (31.12%) and grouped all concealment-associated variables together, named concealment factors. Component II was related to natural disturbance, named natural disturbance factors. Component III was related to water resource, named water resource factors. Component IV was related to food, named food factors. Component V was related to human disturbance, named human disturbance factors. Resulting from the rotated matrix of the eigenvector of the habitat selection of the wolf in winter, all of the eleven ecological factors can be grouped into two types: three main factors and eight secondary factors. The main factor was the concealment factor including the vegetation height, the vegetation type and the concealment levels. The secondary factors were: the natural disturbance factors, including the distance to fence and the snow depth; the water resources factors, including water resource and the habitat type; the food factors, including the distance to pasture and food richness; and the human disturbance factors, including the distance to grass road and the distance to settlements. Results derived from our data suggest that with effective managements to these five types of habitat variables, wolves will reappear in the region once occupied by themselves.