The focus of this research is to discuss distribution of some harmful chemical elements in farmland, as affected by soil utilization, crop rotation, variety of crops or vegetation and duration of cultivation. Results show that contents of harmful chemical elements vary greatly in the test fields from 0.05 to 2.35 for Hg, 4.28 to 42.90 for As, 22.50 to 106.50 for Pb, 49.80 to 101.70 for Cr, 0.09 to 2.16 for Cd and 15.00 to 125.40 mg/kg for Cu. The contents of Cd, Pb, Cu and Zn in the test fields are lower than in that, respectively, in the vegetable soil in Hangzhou, but the content of Ni is the opposite. Compared with those in vegetable soil in Hong Kong, the average contents of As, Cd, Pb and Zn are lower, but Cu is an exception. Crop rotation and crop diversity has a definite but insignificant influence on accumulation of some toxic heavy metals in soil, whereas duration of cultivation has a much obvious one. Contents of harmful chemical elements in vegetable soils low in mellowness are obviously higher than in those moderate in mellowness.