This study took Nanjing as a target area and aimed to establish relationships between compaction and soil water characteristic parameters by determining soil bulk density,porosity and soil water characteristic curves as affected by different land uses,including function zones,vegetation types and years of land use.Function zones were differentiated as residential area,park,campus,road greenbelt in the city zone and vegetable garden in the suburb.Vegetation types included lawn,lawn and tree,arbor and shrub,vegetable and no vegetation.Land 2use ages varied from the newly transported soils(used for less than 5 years)to the old soils(used for more than 20 years in the studied areas).Therefore,the studied soils were typical and could show the major soil uses in Nanjing.Bulk density and porosity were selected as the indicators of soil compaction.Water characteristic parameters included field moisture capacity,wilting point moisture content and available moisture content.The results show that urban soils were severely compacted as compared to surrounding suburb soils.The bulk density of most soils in the city exceeded that of normal soils(1.30 g cm^-3).The porosity decreased significantly,especially aeration porosity.Bulk density and aeration porosity were good indicators of soil compaction,showing significant relationship with field moisture capacity.Wilting point moisture content was also related to bulk density and aeration porosity.With the increase in soil compaction degree,field moisture capacity and wilting point moisture content of the soil increased,while potentially available moisture content decreased obviously.So compaction weakens the capacity of soils in regulating water supply and makes plants more vulnerable to drought.