Soil properties change dramatically during urbanization. However, recent knowledge about properties of urban soils is still scarce. The purpose of this paper is to deliver some data of soil organic matter (SOM) properties of urban soils and to describe environmental consequences of human activities in urban environment. For the above objectives, organic carbon (OC) and black carbon (BC) were analyzed of 60 soil samples collected from 0～10 cm and 10～30 cm soil layers in five different function zones in Nanjing city, China. The method used to analyze OC and BC is chemical oxidation treatment (acid dichromate), in which removal of OC is a critical process in determination of BC. The results suggest that SOM (e. g. OC and BC) is significantly different among function zones in chemical nature and concentration. The highest concentration of OC reaches 29.09 g kg^-1 (0～10 cm layer), and the highest concentration of BC 13.67 g kg^-1(0～10 cm layer) in roadside soils, suggested its substantially different human activity and pollution source. Especially, pollution compounds emitted from gasoline and diesel vehicles are found to be the main source of BC in roadside soils. The BC/OC ratio may be related to changing pollution intensity due to local biomass and fossil fuel burning. Based on the present data, the high BC/OC ratios and BC concentrations observed in roadside soils indicate that they are the result of direct human activity (e. g. vehicles). In other words, the BC/OC ratio in different functional zones may show different intensity of human activities. Further comparison shows that BC is probably the main part of total organic carbon in urban soils, contrary to that in natural soils. This knowledge is essential for qualitative assessment of SOM properties of urban soils and urban environment.