The structural characteristics of pore represent a fundamental aspect of the microscale heterogeneity in weathered granite soils，significantly affecting both the water transport processes and the macroscopic mechanical behavior in soils.A fully weathered gully profile was used to analyze the water transport processes and elucidate the seepage mechanisms in granite residual soils.X-ray computed tomography （CT） was conducted on the weathered soil of intact granite in the entire profile.Three-dimensional （3D） reconstruction and pore network modeling （PNM） were performed with Avizo software to quantitatively characterize the pore structure across the entire profile of soil.The results showed that the porosity in soil had a decreasing trend with the increase of weathering depth ranged from 4.2% to 25.1%，with the porosity in the upper layer of soil （layers A and B） significantly higher than that in the lower layer of sand （P<0.05）.The equivalent diameter of pores in all layers of soil was predominantly distributed in the range of 0.1-0.2 mm，with inclination angles mainly concentrated in the range of 40°-50°，and the distribution of azimuthal angles across layers was relatively consistent.Macropores （>100 μm） were mostly regular and spherical in shape with sphericity of 0.8-1.0，and more regular pores were observed in the upper layers.The connected and isolated pores showed opposite trends from the top to the bottom of the weathering profile，indicating that there is a gradual decrease in pore connectivity with depth.The radius （0.1-1 mm） of connected pore，coordination number，and the surface area of pore decreased gradually along the weathering profile in the pore network models （PNM） of different layers.The average length of pore throat in the upper layers was generally higher than that in the lower layers.Flow simulations based on the PNM had a strong agreement with measured saturated hydraulic conductivity，with a high coefficient of determination （R2 = 0.96）.There were significant positive relationships among key PNM parameters including the diameter of pore throat，channel length，and the radius of connected pore （P<0.05）.The morphological and directional parameters of pore including the sphericity，inclination angle，and azimuthal angle were significantly positively correlated with tortuosity （P<0.05）.The connectivity of pore，fractal dimension，porosity，coordination number，and throat area were identified as key factors affecting the saturated hydraulic conductivity，indicating that the geometric attributes of pore collectively govern the structure and function of the pore network.It is indicated that 3D reconstruction and quantitative analysis of structures of pore network in weathered granite soils can be used to clarify the differences in topological and spatial structure of pores inside weathered soil，and explain the key reasons for the formation of heterogeneity，anisotropy，and metastable structure of granite soils under weathering.