Abstract: In order to demonstrate the feasibility of eliminating foundation collapasibility for the two-way soil displacement screw pile (SDS pile) on self-weight collapsible loess, the compaction test of the single and group pile were carried out on the site of high-order deep thickness self-weight collapsible loess on the south coast of the Yellow River in Lanzhou.The deformation of soil around the single pile and the changes of physical and mechanical indexes of soil at different distances from the pile were measured; the changes of the physical and mechanical indexes and the bearing capacity of the soil among piles were measured.The research showed that the variable maximum range of soil properties treated by the SDS pile was in 2 times pile's diameter, the obvious influence range was 1.0 to 1.5 times pile's diameter; when the distance between piles was not more than 2.5 times diameter. The SDS pile could eliminate the collapsibility of the loess.