Abstract: The persistent and escalating demand for petroleum has underscored its status as a significant organic pollutant in both groundwater and soil environments. Particularly, the light petroleum products, such as diesel and gasoline, exhibit heightened migration capacities owing to their lower viscosity so, the leakage of light petroleum presents a substantial pollution potential to both groundwater and soil environments. To undertake a comprehensive and accurate analysis of the distribution and migration patterns of diesel oil after site contamination, this paper employs a one-dimensional soil column as the physical model. The research focuses on the utilization of 0# diesel oil as the primary object of study and relies on the fundamental principle of Darcy’s law. The investigation entails a one-dimensional soil column test conducted within an indoor porous medium characterized by three distinct particle sizes: fine sand, silt sand, and quartz sand. The study aims to scrutinize the rate of movement of diesel oil under the influence of varying medium particle sizes, different fluids, and diverse water contents in the non-saturated state. Moreover, it delves into the exploration of the change characteristics observed in different saturated media, with a specific emphasis on alterations in saturation and two-phase flow concerning the seepage time coefficient. Key findings from this study reveal that the infiltration rate of diesel fuel exhibits a direct proportionality to the particle size of the medium. Specifically, the infiltration rate hierarchy from large to small is identified as quartz sand ＞ fine sand ＞ silt sand. Within the same medium, the rate of movement of the oil phase is observed to be smaller than that of the water phase. Quartz sand, fine sand, and silt sand, the three media under consideration, display voil values smaller than vwater by 44.6%, 65.3%, and 64.3%, respectively. Across the research media, the rate of diesel fuel movement displays a nuanced trend of increasing and then decreasing with the rise in the water phase saturation of the medium. A comparative analysis of the movement rate under optimal moisture content further elucidates that the influence of particle size on the movement rate is smaller than the influence of water content. Notably, the movement rate reaches its maximum when the medium is at optimal water content. At this time the impact of particle size on the rate of movement is very small. In addition, diesel and water interactions are found to exert a significant impact on the infiltration coefficient. As media saturation diminishes, the interactions between diesel and water gradually weaken, leading to a convergence of diesel infiltration coefficients towards their counterparts in the water-saturated state. In addition to the research findings, this paper engages in an insightful discussion on various aspects, including oil-water movement rates, permeability rates, residual water phase permeability enhancement mechanisms, and the transportation characteristics of diesel fuel in the context of packaged gas belts. Overall, this comprehensive study not only provides a scientific foundation for the development of more effective pollution prevention strategies but also contributes invaluable insights into optimizing pollution treatment technologies, improving treatment efficiency, and mitigating environmental risks. Simultaneously, the study offers theoretical guidance and a robust basis for the treatment and remediation of diesel site pollution.