The macro strength and deformation characteristics of coarse-grained soil are closely related to its micro pore structure. In order to deeply understand the strength deformation mechanism of coarse-grained soil, this paper takes the heterogeneity of pore structure as the research object, and defines the pore space distribution coefficient which can quantitatively describe the pore space variability of coarse-grained soil by analyzing the quantitative variability, volume variability and segregation effect of pores. The results show that the elastic modulus, peak strength and Poisson's ratio of coarse-grained soil decrease by 40.8%, 12.5% and 39.5% respectively with the increase of pore space distribution coefficient under other conditions.