This　paper　aims　to　reveal　the　water　transport　mechanism　in　soils　with　macropores.　Based　on　the　combination　of　the　X-ray　CT　scanning　and　image　processing　technologies,　a　three-dimensional　(3D)　equivalent　pore　network　model　(PNM)　with　macropores　(＞0.15　mm)　is　constructed,　and　the　size　of　the　optimal　representative　volume　unit　(REV)　is　determined　to　be　300×300×300.　Then,　the　quantitative　characterization　of　the　topological　structure　of　the　macropore　space　is　carried　out　followed　by　the　PNM　single-phase　flow　and　the　3D　macropore　water-gas　two-phase　flow　simulation.　The　results　show　that　there　are　more　pores　with　smaller　pore　diameters,　and　more　than　80%　of　the　pores　are　concentrated　within　0.15–1.00　mm.　The　pore　topological　space　structure　is　quite　different,　and　the　coordination　number　is　mainly　less　than　20,　but　some　can　reach　more　than　60.　The　average　coordination　number　of　pores　is　between　3–7,　and　the　average　connected　pore　radius　is　greater　than　2.00　mm.　The　single-phase　flow　simulation　find　that　the　complexity　of　the　pore　structure　and　the　resolution　of　X-ray　CT　scanning　resulted　in　a　certain　difference　between　the　simulated　and　measured　permeability,　but　the　difference　of　the　main　seepage　direction　is　only　3.81%.　The　two-phase　flow　simulation　find　that　the　front　edge　of　flow　is　almost　linear　at　the　beginning　of　seepage,　then　it　tend　to　be　fingering,　and　finally,　it　become　irregular.　The　residual　gas　in　the　pores　is　mainly　distributed　in　blocks　at　the　edges　of　pores,　dead　ends,　and　sudden　changes　of　pore　throats.　With　the　increasing　seepage　time,　the　saturation　of　the　water　phase　shows　an　upward　trend,　while　the　saturation　of　the　gas　phase　shows　a　downward　trend,　then　gradually　tend　to　be　stable,　and　finally,　the　saturation　of　the　water　phase　and　the　residual　gas　phase　maintain　at　94.92%　and　5.08%,　respectively.　This　study　can　better　reveal　the　meso-seepage　mechanism　of　reconstructed　soil,　and　provide　a　certain　reference　for　further　understanding　the　law　of　pore　flow　in　soil.　©　2022　Chinese　Academy　of　Sciences.　All　rights　reserved.