Abstract: The effect of acrylic acid super absorbent ploymer on the soil water content using regression-orthogonal design experiment at indoor laboratory was studied. The mathematics model for the relationships among soil available water content with soil texture, particle diameter and dosage of super absorbent ploymer(SAP) was deduced. The result shows that the effect of soil texture and dosage on soil available water content is significant, but the effect of particle diameter of water-holding reagent(SAP) on soil available water is not significant. Therefore, this type of super absorbent ploymer can be used rationally in production based on the mathematics model.