Based on the analysis and study on soil physical properties of different karst ecosystems in Guizhou Wujiang river basin,it is thought that the karst ecosystem is the main factor influencing the soil physical properties.In the good ecosystems,the soil profile develops very well and stratifies obviously and its layer is deep;the organic content is relatively high;the soil relies mainly on glueing loam and clay;its hole property is suitable,and structural property is good;the quality of resisting erosion and collapsing is strong.While in the degenerated ecosystems,its physical properties are worsened and the quality of resisting erosion and collapsing is weakened.Therefore,the main indices are made to evaluate the soil quality of resisting erosion in different karst ecosystems and its ability to anti-erosibility and collapsing is gotten as follows: shrub plus weak erosion and forest plus slight erosion> weeds plus silt and dry land plus middle erosion> infertile land plus strong erosion.