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，F1,400=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.