Abstract: In order to study the adsorption of water vapor and nitrogen by sliding zone soils of Huangtupo landslide, the specific surface area and pore size analyzer instrument of Autosorb-iQ of United States and the F-sorb3400 of China are taken. The adsorption tests on water vapor at 293 K and nitrogen at 77 K under drying samples and vacuum freeze-dried samples of sliding zone soils are carried out. The theories of Brunauer-Emmet and Teller (BET) and Frenkel-Halsey-Hill (FHH) are taken to calculate the specific surface area and surface fractal dimension. The test results show that the specific surface area calculated by water vapor adsorption is larger than that by nitrogen. The adsorption volume of water vapor on per unit mass sliding zone soils is more than that of nitrogen. It is found that smaller water vapor molecules can get into the micropore and adsorb on the clay mineral surfaces and intralayer with function of polar, which makes the surface cations of clay mineral hydrate and makes the adsorbed water surface more smooth. On the contrary, the bigger nitrogen molecules cannot get into all the micropore and the surface of nitrogen adsorbed seems to be more uneven. The adsorption capacity of water vapor in dried samples is weaker than that of the freeze-dried samples because of weak hydrogen bonds.