There is no doubt that soil database is an important mnemonic and analytic tool for soil studies.This paper deals with spatial heterogeneity of soil properties with the aid of a 1:50 000 soil database of Wuxi and Changzhou cities, which is built up with the ArcGIS and Visual FoxPro technology and consists of 8 830 mapping polygons and data of 269 soil profiles.A map is compiled in the accordance to the criteria for grading of soil fertility fixed up in Research Project "973" on Principles of Soil Quality Changes and Sustainable Land Use (for pH, available phosphorus and potassium) and in the National Soil Nutrient Grades (for total nitrogen) to show the spatial heterogeneity of pH, total nitrogen, rapidly available phosphorus and potassium in the surface soils (0～15 cm) of the study area.The map shows that soils of grade 1～2 in pH value constitute about 90% of the total study area, and that the most part of the soils on the flat Tai Lake-Ge Lake Plain are commonly in grade 1 in total nitrogen, rapidly available phosphorus and potassium.Moreover, variance analysis is conducted of the data of physico-chemical properties of the soils of various parent materials and of various types (soil subgroups).Result shows that all determined soil properties, except for total nitrogen, are quite heterogeneous.It is concluded that, at the scale of 1:50 000, parent material is the dominant factor for the spatial heterogeneity of pH, bulk density, total phosphorus, organic matter and rapidly available potassium,while soils type for the spatial heterogeneity of pH.That is to say, the impacts of parent materials have stronger impacts on spatial heterogeneity of soil properties than soil types do.