Both the toxic pollutants’ bioavailability in soil and its migration-accumulation in soil-plant system are current hot topics. 61 soil samples and corresponding 7 kinds of leafy vegetable samples were collected from Dongguan which is a township-enterprise dense area in Guangdong Province, the total contents and extractable concentrations of 5 heavy metal elements (Cu, Zn, Cr, Ni and Pb) were measured. Results showed that the leafy vegetables faced obvious problems of both the excess of toxic metal (Pb, Ni) and the shortage of useful metal (Zn, Cu). The metal concentrations in leafy vegetable had no significant correlations with either the total or the extractable heavy metal concentrations in soil. While the heavy metal concentration in leafy vegetable evidently related to the accumulation factors which are calculated from extractable heavy metal concentration. The accumulation factors of heavy metal in different kinds of leafy vegetables decreased with the increase of the extractable heavy metal concentration, which can be described best by the exponential equation (y = axb). The descending trend has close correlation with the concentration range of extractable heavy metal in soil. The optimal estimation of accumulation factors resulted from the exponential equation was more precise than both the mean and the medium in the case of limited samples.