Abstract: The shallow buried and thick silty fine sand is widely distributed in Yinchuan Plain. It is the main load bearing layer for building structures, and the mechanical properties test data for engineering reference are not enough. Therefore, considering the two important factors such as the dry density and the saturation, the statistical orthogonal test scheme was designed in this study. The compressibility of silty fine sand in Yinchuan Plain was studied by means of onedimensional tests by using automatic pneumatic consolidation apparatus. The influence factors and mechanism of each factor were investigated, the significance was analyzed, and the empirical correlation with the compressibility was established. The results show that the compressibility of the silty fine sand is low, and the maximum value of  a_1-2 is no more than 0.2 MPa^-1within 1~7 m depth of Yinchuan Plain, which is a mediumlow compressibility soil. With the increase of dry density, the compressibility decreases nonlinearly, and the change of compressibility decreases. With the increase of saturation, the compressibility increases nonlinearly, but the change of compressibility decreases. For a_1-2, the effect of dry density is very significant, and the effect of saturation is significant. The order of significance is dry density and saturation from high to low. Increasing dry density is a very effective measure to reduce the compressibility of Yinchuan sandy soil, while increasing saturation has a better effect on improving the compactness of Yinchuan sandy soil. The compressibility model has good correlation and high significance, which is of practical significance to the prediction of compressibility of silty sand in Yinchuan Plain.

Key words: Silty Fine Sand, Compressibility, Relational Model, Yinchuan Plain