In this study the physical properties of surface soil were investigated under diffecent conditions. From the results obtained, we may come to the conclusion that good soil physical properties, which are resistant to soil erosion, are exhibited by high content of organic matter, large quantity of > 0.25 mm total aggregate and 1-10 mm aggregate, and the state and degree of micro-aggregation. We have also studied the twa soil physical constants, dispersion ratio and erosion ratio, which Middleton used to separate erosive from nonerosive soils. The results showed that both ratios increased following the cultivation of grass land, and that the heavier the soil, the smaller the ratios. These findings agree with that of Middleton. However, he used the erosion ratio "10" as a demarcation point between erosive and nonerosive soils. In our study, we found the erosion ratio of the heavy soil, which was the lowest, even reached as high as "19.0". Looking at this, it seems that all soils in this region should be erosive. Hence, further study is needed on the point of demarcation of erosion ratio when used in loess region.