The　environment　of　estuarine　wetlands　has　been　attracting　worldwide　attention.　To　study　the　spatial　distribution　of　pollutants　in　the　tidal　fiats　of　the　Yangtze　Estuary,　Southeast　China,　the　Eastern　Tidal　Flat　of　Chongming　Island　(EC)　and　the　Jiuduansha　Shoal　(JS)　of　the　estuary　were　selected　as　the　study　sites.　At　each　of　the　two　sites,　a　cross-transect　from　land　to　sea　was　established　and　topsoil　and　soil　core　samples　in　the　cross-transect　were　collected　spatially　and　seasonally　to　determine　their　contents　of　heavy　metals　(Cu,　Zn,　Pb,　Cd,　Cr,　Ni,　Mn,　and　Fe)　and　grain-size　characteristics.　The　results　showed　that　the　heavy　metal　loads　were　commonly　higher　in　the　soils　of　nearshore　high　tidal　flats　and　had　a　tendency　of　decreasing　from　land　to　sea　at　both　of　the　study　sites.　The　contents　of　heavy　metals　in　the　soils　of　the　high　and　medial　tidal　flats　were　mostly　higher　in　April　and　November　but　lower　in　July.　Corresponding　spatial　and　seasonal　variations　in　grain　size　of　the　intertidal　soils　were　also　observed　at　the　two　study　sites.　The　soils　in　the　nearshore　high　tidal　flats　were　finer　and　gradually　got　coarser　seawards;　they　were　relatively　finer　in　April　and　November　but　coarser　in　July.　Furthermore,　the　contents　of　heavy　metals　in　the　intertidal　soils　of　both　the　sites　EC　and　JS　were　significantly　positively　correlated　with　the　clay　(＜2　mu　m)　and　2-20　mu　m　fractions,　but　negatively　with　the　sand　(＞　63　mu　m)　and　20-63　mu　m　fractions,　which　suggested　that　the　heavy　metals　in　the　intertidal　soils　were　primarily　combined　with　the　fine　particulate　fraction　(＜　20　mu　m),　especially　clay,　and　hence　the　spatial　and　seasonal　variations　in　heavy　metals　were　actually　caused　by　the　change　of　the　grain-size　characteristics　of　the　intertidal　soils　due　to　the　different　sedimentary　environments　in　the　estuary.　The　results　of　this　study　may　also　contribute　to　a　better　understanding　of　the　soil　formation　and　classification　in　the　tidal　flats　of　the　Yangtze　Estuary.