Abstract: Dens of Tibetan fox in Shiqu County, Sichuan Province were surveyed to understand their characteristics and the mechanism of habitat adaptation of the Tibetan fox. Four fixed line transects with a total length of 40 km, covering 230 km² research area were set from July to August 2001, 2002, August to November 2003, and March to April 2004. The mean entrance number of Tibetan fox dens was 1.8±1.8 (n=156). Multi-entrance dens (n=47) were more distributed on slope than mon-entrance (n=109)(U=1 417，P＜0.001). The mean of width, height and the first tunnel length of 91 measured dens were (17.0±2.5) cm, (24.9±7.2) cm and (169.9±88.4) cm respectively. Tibetan fox dens were mainly constructed by soil (74.7%). Rock dens were significantly more distributed on slope than the other two kinds of dens (χ²=10.227，P=0.006). Den entrance exposure did not show concentration on mean angle (Rayleigh，Z=0.898, n=201,P＞0.05), but slope direction concentrated significantly on the mean angle (249.9±77.1)°(Rayleigh，Z=7.907,n=201,P＜0.05). No correlation was found between entrance exposure and slope direction (Hotelling，F_1,400=5.365,P＜0.05) but the first tunnel obliquity correlated with the gradient (t=0.350,n=116，P＞0.05), four breeding dens were found during our field research. These breeding dens were all made of soil with the slope direction from 220° to 320°. No fox dens were found on the plain area.