Biological soil crust (BSC) develops extensively in water-wind erosion crisscross region of the Loess Plateau, northern Shaanxi Province of China. We compared the effects of two types of BSC on soil physicochemical properties in Liudaogou watershed in the region. The two types of BSC, one developing on sand soil and another on loess soil, are moss dominated with main species of Bryum arcticum(R. Brown) B.S.G. and Barbula vinealis Brid. The results show that: (1) Both types of BSC increase saturated soil water content and field capacity, decrease bulk density and saturated hydraulic conductivity. BSC on sand soil can increase soil clay content in 0-25 cm layers; (2) Both types of BSC increase total N, total P, available N, available P, available K and organic matter, and decrease pH value, although most of these effects are observed in surface soil only; (3) Compared with other soil chemical properties, BSC have greater effects on soil total N, available P and organic matter, and deeper effects on total N, available K and organic matter in soil profile; (4) BSC on sand soil have greater effects on soil physicochemical properties than BSC on loess soil. As a whole, both types of BSC are beneficial for ecological construction in the research region, although the ecological function of BSC developing on sand soil maybe more important than BSC on loess soil.