The study on the relationship between soil factor and physiological response of the plants is very important for understanding ecosystem damaged mechanism from sandy desertification and improving efficiency of fathering sandy desertification. However, little is studied or made known about what are the key soil factors for different plant and the effect of degradation level on the interactions between soil factors and physiological response of the plants under natural environment on sandy grassland. The aim of the present study is to find the relationship between the soil factor and physiological response of the plants under different desertification stage and the practical measure to fathering desertification on grassland. Three-year’s research work is from 2001 to 2003 in DUOLUN County, Xilin Gol, Inner Mongolia. A series of degradation gradient or stage is established by clustering analysis, and become Ⅰ,Ⅱ, Ⅲ, Ⅳ and Ⅴstage corresponding to original vegetation(OV), potential desertification（PD）, light desertification（LD）, moderate desertification（MD）and heavy desertification（HD）, as well as corresponding to five community types of L. chinensis + Stipa kryovii + bunch grass, C. squarrosa + Agrostis cristatum, A. frigida + A. cristatum + C. squarrosa + weed , A. intramongolica + weed and annual plant. Five community types were selected as the sampling sites. Choosing four common plant population (i.e. Leymus chinensis, Cleistogenes squarrosa, Artemisia frigida and Melilotoides ruthenica) is to be provided with comparative significance because their different physiological response to sandy desertification. The correlation analysis was done between the soil factor（5 soil indexes）and the physiological response of per plant population( 7 physiological indexes). The results showed as follows : (1)In the course of the grassland sandy desertification, L. chinensis being a impressible type among four common plant population, its physiological response had very significant correlations with the soil moisture and C/N in soil than other soil indexes（P<0.01）relatively. According to this, it was proved that the soil moisture and C/N in soil were the key factors to result in the damage on the physiological level of L. chinensis. Both its MDA and ABA had more significant correlations than other physiological indexes with five soil indexes as a whole（P<0.01）. Therefore, it is possible that ABA is important factor on damage. It may arouse the membrane lipid peroxidatic reaction. (2)C. squarrosa and A. frigida being a resistant type, only the C/N of soil among 5 soil indexes relation with both MDA was consistent. And that their correlations were very significant（P<0.01）. Both ABA relations with 5 soil indexes were consistent. Similarly, their correlations were very significant（P<0.01）.The C/N in soil significantly influenced physiological level of A. frigida. Furthermore the content of total N in soil, the soil moisture and content of clay in the soil were important to A. frigida. (3)M. ruthenica being a retarded type, it was more sensitive to the soil physics character (the soil moisture and content of clay in the soil) than the soil chemistry character (the content of C, total N and the C/N in soil), suggesting that degradation of the soil nutritious elementary was not the leading factor of holding back its growth . Its MDA showed most significant correlation（P<0.01） than other physiological indexes with five soil indexes as a whole, but its ABA did not show significant correlation with each of 5 soil indexes（P>0.05）. (4)The result of synthesizing the correlation analysis among the plants of various type showed that MDA and ABA in the plants responded intensively to the stress of desertification environment. (5)For each of the stress resistant types, there were differences in the response mechanism to the soil factor under different desertification stage on sandy grassland. The impressible type responded intensively to the soil moisture and C/N in soil. The response of the resistant type to the soil factor did not show becoming dominant factor. Altogether, the physiological response of the plants among four common populations had almost significant correlation with the C/N in soil.