Abstract: To explore the spatial distribution and morphological characteristics of the pores in foamed lightweight soil. The pore structure of three wet densities of foamed lightweight soil were captured by X-ray computed tomography. Based on Gaussian mixture model, the grey scale threshold of pore and solid was determined by deconvolution and the grey scale images were divided into pore and solid binary materials according to this threshold. The characteristic parameters such as porosity, pore size, sphericity and pore shape were quantitatively characterized described and correlated with strength. Results show that as the wet density increases, the pore size distribution becomes more uniform, the average pore size decreases, and the number of spherical pore increases, which indicates result that the foamed lightweight soil has a more uniform stress distribution, greater resistance to external load and higher strength.