Soil physical properties,to some extent,determine the hydrological characteristics of soil layers.The influences of different vegetation types on soil physical properties can significantly change the functions of soil and water conservation in soil layers of different regions.We discussed the effects of different vegetation types on soil physical properties in Tianlaochi,a small watershed located in the upstream of Heihe River basin.An experiment was carried out under the five vegetation types of Picea crassifolia,Sabina przewalskii,subalpine meadow,shrubs and steppe.Results show that(1)Picea crassifolia had the minimum soil bulk density and the largest porosity.Particles were mainly composed of silt.Steppe and meadow steppe had the highest soil bulk density and the minimum porosity.For the same vegetation types,soil bulk density and total porosity were consistent at different slope positions.With the increase of the depth,soil bulk density increased and total porosity decreased.(2)In meadow steppe,physical properties of the 0-20cm soil layer were similar,and physical properties of the 20-50cm soil layer were with greater consistency.