In order to reveal the influence of anti-erodibility in the cultivated land after returning farmland to forest, based on the field investigation and lab analysis, purple soil samples of 6-year Eucalyptus grandis plantations including pure Eucalyptus grandis, Eucalyptus grandis+grain crops, Eucalyptus grandis+fruits and farmlands were chosen as researching materials, the main physical and chemical indexes of soil anti-erodibility were analyzed by using principal component analysis method. Further, the coupling model of soil physical and chemical properties index and anti-erodibility index was built up by grey relational degree, and the corrosion resistance of different Eucalyptus grandis plantations was synthetically determined. The results showed that the main factors affecting soil anti-erodibility were >0.25 mm aggregate content, bulk density, organic matter, mean weight diameter, water stability index, available potassium and alkaline hydrolysis nitrogen, and >0.25 mm aggregate content was the most important factor to determine the level of soil anti-erodibility. There was a medium correlation between mean weight diameter and soil physical and chemical property indexes, there was a strong correlation between water stability index and soil physical and chemical property indexes. Effects of soil physical and chemical properties on soil anti-erodibility was followed by >0.25mm aggregate content>alkaline hydrolysis nitrogen>available phosphorus>organic matter>available potassium>bulk density. The system's overall level of coupling between soil anti-erodibility and soil physical and chemical properties was weak coordination. On a smaller scale, the coordination degree of system coupling was pure Eucalyptus grandis (moderate coordination)>farmlands (weak coordination)>Eucalyptus grandis+grain crops (mild incoordination)>Eucalyptus grandis+fruits (mild incoordination). Above all, the research conclusions could provide some theoretical basis for the evaluation of soil anti-erodibility in the cultivated land after returning farmland to Eucalyptus grandis plantations.