Abstract: This paper studied on the influencing factors of soil anti-scourability of tree-crop intercropping land in purple soil hilly region by used the methods of undisturbed soil sample washing and soil physicall properties analysis indoor. The result showed that: （1）Soil bulk density had remarkable positive correlation with the index of soil anti-scourability and soil porosity had remarkable negative correlation with the index, and this result showed that the soil bulk density more big ,the soil porosity more small, and the soil will be more solid ,the soil anti-scourability will be improved under the short time and high intensity washing condition;（2） The fine sand（0.25～0.05mm）content had remarkable positive correlation with the index of soil anti-scourability ,and which showed that the coarse granule could enhance soil anti-scourability ;（3）The >5mm water stable aggregates content had great remarkable positive correlation with the index of soil anti-scourability and the >0.25mm water stable aggregates content also had remarkable positive correlation with the index, which showed that big water stable aggregates content was more, the soi structure will be finer, the soil anti-scourability will be enhanced ; （4）The steady water infiltration rate had great remarkable positive linear correlation with the index of soil anti-scourability and the initial water infiltration rate had remarkable positive linear correlation with the index ,too; （5）The root biomass in different diameters all had great remarkable positive correlation with the index of soil anti-scourability,and the root density had remarkable positive correlation with the index of soil anti-scourability, the root length of <3mm root also had remarkable positive correlation with the index of soil anti-scourability. The root system can enhance soil anti-scourability effectually. Soil bulk density, fine sand（0.25～0.05mm）content, >5mm water stable aggregates content, steady water infiltration rate and the root biomass of <1mm root can forecast and evaluate the purple soil anti-scourability in this area.