Abstract: In order to analyze the effect of sampling mode on collapsible soil with strong structure,two collapsibility tests were carried out in the site,and the collapsibility characteristics of shallow fine grained soil in the site were basically identified.The laboratory test was carried out on the soil samples of three different sources of impact drilling rig,artificial digging and rotary drilling rig.The test results show that the impact drill sampling of collapsibility coefficient decreased obviously,analyze the reasons for the impact of sampling has great influence on the collapsible soil density and compression modulus;while rotary drilling sampling has a significant impact on the collapsible soil water content.Because of filling of soil pore by water,directly led to the increase of soil saturation and density.Through the analysis of the relationship between the collapsibility coefficient and the density,the size of collapsibility coefficient is anti-correlation with the size of density,and the density was about 1.90~1.95 g/cm³,the soil in the field no longer has collapsibility.The data have some reference significance for the research and production of collapsibility-treatment.