Heavy metal contents in topsoils of 127 urban sites in Baoshan District, Shanghai were detected to study impact of urbanization on urban environment. Results indicated that the average value of Zn, Cr, Cd, Pb, Cu, Ni and Mn in the topsoils was 228.6, 127.6, 0.56, 118.5, 55.2, 55.7, and 718.7 mg/kg, respectively, among which, the value of Pb, Zn and Cd was 5.6, 3.0 and 2.8 times their respective background value in Shanghai. Spatial variation of heavy metal contents in the urban topsoil was also observed: Heavy metals in the topsoil of the industrial sites, such as Wusong and Dachang Towns etc., were the highest, with Zn, Cr, Cd, Pb and Cu being 407.6, 319.0, 0.75, 101.2, and 76.2 mg/kg on average, respectively; Pb was significantly accumulated in the topsoil of the Greenlands alongside highways, with the average being 180.2 mg/kg; but heavy metal contamination of the vegetable soils in the suburbs, such as Gucun, Luojing and Luodian Towns, was not significant.