With spatial and temporal variation of soil fertility in vegetable soil during the course of urbanizations in Nanjing, the capital of Jiangsu province, as a case for study, laws and causes of the spatial and temporal variation were analyzed. The results showed that urbanizations promoted variation of soil fertility of vegetable field: The content of total P, total organ matter and total N in urban area was higher than that in suburban and rural area, which is associated with mellowness of the soil and time length of its cultivation. The value of pH went down gradually from urban to rural areas. The content of total N, total organ matter, available K and pH in 1999 was higher than that in 1980, respectively whereas the content of total phosphate in 1999 was lower than that in 1980.