Mass transport in soils occurs through the soil-pore network, which is highly affected by the physical properties of soil particles (i.e., particle size and shape). However, there have been few studies on the relation among particle size and shape, soil pore network, and mass transport parameters such as hydraulic conductivity, gas diffusion coefficient, and air permeability. In this study, using the sands with different size fractions and particle shapes, the pore structure (i.e., pore size distribution, pore tortuosity) was analyzed by micro focus X-ray CT images, and mass transport parameters for the samples were measured. The results showed that at the same conditions on the total porosity and effective pore radii, the round sands have higher hydraulic conductivity as compared to the angular sands due to their higher coordination number and lower surface area of soil particles. Based on the X-ray computed tomography measurements, how pore structure for different sands affects the gas transport parameters (air permeability and gas diffusion coefficient) will be also discussed.