To study and explore heavy metals distributive characteristics and their controlling factors, 459 typical soil samples were systematically collected from the farmlands in Jiangsu Province, and heavy metal concentrations (Cd, Hg, Pb, As, Cr, Ni, Cu, Zn) and their speciation contents (exchangeable state, reducible state, oxidative state, residual state) were determined with the improved 4-state testing methods related to chemical state analysis from European Community BCR. Macro elements and other relevant soil physio-chemical parameters were also analyzed such as pH, TOC, and CEC, and geochemical parameter statistics and correlation analyses were used to analyze and compare these detected data. The results showed that: 1) exchangeable and reducible state were the main speciation of Cd (accounting for more than 75%), residual state was the main speciation components of Hg and Cr (more than 90%), reducible and residual state were the main speciation of Pb, As, Ni, Cu and Zn (more than 87% in total), while oxidative state was less than 8.5% for every heavy metal; 2) There were mostly significant positive correlation between heavy metals speciation contents and the total contents (correlated coefficients r general higher than 0.5, and r of Cd higher than 0.9), and the positive correlation between rice Cd with soil exchangeable state Cd was obviously higher than with soil total Cd; 3) soil pH, TOC, CEC, Si, Al, Na, K were outright important factors to impact heavy metals speciation distribution, but controlling factors were obviously different for different heavy metals and their speciation, for example, there were significant negative correlations between exchangeable state, reducible state, oxidative state Cd with pH or K, and significant positive correlation between oxidative state Cu and Zn with TOC; 4) Some similar or identical material sources or enriched mechanism may existed for Cd, Cu, Zn and Se in the farmland soils, resulting in significant positive correlation between Se with exchangeable state, reducible state, oxidative state of Cd, Cu and Zn; 5) BCR speciation method was irreplaceable to detect soil heavy metals and their speciation except Hg because of the low qualified rate of Hg (only 4.6%).