A simulated experiment and a pot test were conducted to study the time-dependent changes of soil mercury fractions and the influence of liming on them. the acid purple soil and the yellow soil were treated on different lime levels but the same HgClz level. Hg fractionation was carried out by using the sequential extraction method at 5, 14 and 30 days after treatment in the simulated experiment and at 35, 320, 610 days in the pot test. The different mercury fractions were distributed in the order of residual Hg > acid soluble Hg > alkaline soluble Hg and active Hg after HgCl₂ application. Their stability decreased in the same trend, and the other three fractions would gradually transform into residual Hg. The influence of liming on the distribution of mercury fractions occurred only within a certain time range and a proper dose range.