Abstract: Content, vertical exchange, correlation of total content and speciation content were determined by geochemical speciation analysis of As and Cd in farmland soil in Dayu County , Jiangxi Province. The results showed that the contents of residual As and ion exchange Cd were 22.14mg/kg and 0.437mg/kg, which accounted for 76.88% and 54.97%, respectively. The percentage of mobile As and Cd of in abnormal topsoil were 4.03% and 70.29%, 1.55 and 0.61 times higher than that of the controlled areas, respectively. The contents of As and Cd in the farmland soils affected by sewage irrigation or flood had the characteristics of vertical distribution existed as significant enrichment in topsoil of 0~20cm, varying degrees of decline under 20cm.With the increase of As and Cd in topsoil, the percentage content of the residual As and ion exchange Cd increased, while the other speciation contents decreased or with no significant change