Abstract: The Loess Plateau is well known for its severe soil erosion because of the erodible soil, unreasonable land use and natural vegetation damage. Intense soil loss results in depletion in farmland, deteriorating ecological environment and plethoric silt in channel and so on. Therefore, an important policy was established to return the cropland to forest and grassland on the Loess Plateau. After carrying out the policy, most of croplands have been left alone in their wildness on the Loess Plateau. But little research has been conducted on the change of the soil properties on these lands, especially for the properties closely related to soil erosion. The permeability and anti-scourability are two very important indexes of soil properties. The permeability indicates the potential to produce runoff which is one of the main forces of soil erosion. The anti-courability is the ability of soil to defend the scouring of the flow. The typical region of Ansai was selected to study the permeability, anti-scourability and other soil properties of these lands after being wild for different years. Anti-scourability was measured in a hydraulic flume with slope gradient 15癮nd flow discharge of 1,2,3,4,5L/s. The saturated hydraulic conductivity, organic matter, bulk density, saturated water content, capillary water content and field capacity were aslo measured. The results indicated that the scoured soil module changed most markedly, and the saturated hydraulic conductivity, non-capillary porosity, and organic matter also varied greatly, with the indexes of bulk density, saturated water content, capillary water content, field capacity, total porosity, and capillary porosity altering comparatively little. The permeability linearly increased about 0.044mm/min a year after being wild with solidifying by plant roots, increasing organic matter and non-capillary porosity. The scoured soil module exponentially decreased. That is to say, the soil anti-scourabiltiy improved greatly with the increasing time of being wild, in which plant roots also play a very important role. In addition, soil bulk density indicated some relationship with the soil anti-scourabiltiy and permeability. It was shown that the soil and water loss was controlled to a great extent and soil quality also improved after being wild for over 5 years.