Abstract: In this paper, PAM was used and trained in soil column to study the effects of PAM on soil water stable aggregates of the dark loessial soil, loessial soil, aeolian sandy soil. In addition, the mechanisms of the effects of PAM and its optimal concentrations were offered. The results show that PAM could promote the formation of the > 0.25 mm water stable aggregates within the concentration of 0.05%～0.4% and reduced the fractal dimension of aggregates effectively in the studied soils. The results of variance analysis indicate that PAM has the similar mechanisms in improving three types of soil, the application of PAM makes <1 mm aggregates into bigger aggregates and increases the content of >1 mm aggregates. However, the concentrations are different for improving studied soils and achieving the remarkable effects because the clay and organic matter contents are different in the studied soils, which indicate that clay and organic matter contents are probably the major factors influencing the effects of PAM. The effective concentrations of PAM for the dark loessial soil, loessial soil, aeolian sandy soil are 0.2%～0.4%, 0.05%, 0.05%, respectively.