Abstract: As contaminated-soil samples were prepared artificially with As concentration being 100 mg·kg^-1 for the study on the use of FeCl₃-citric acid, a compound leachate prepared by means of ultrasonic dissolution, to leach As from As contaminated soils and effects of ratio, pH, temperature of the leachate and commonly coexisting anions or cations (Ca²⁺, Al³⁺, SO₄^2- and PO₄^3-) on leaching characteristics and their mechanisms. Results show that in solutions the same in soil-to-liquid ratio (1:10), the compound leachate maximized its effect of leaching As from As-contaminated soils when its m(FeCl₃):m(citric acid) was 3:1 and was better than simple leachates in leaching effect. Rising pH and temperature within a certain range contributed to leaching. In solutions with pH being 7, 8, 9 or 10 and temperature at 25, 35 or 45℃, the leaching kinetics could be better described with the Elovich equation, which indicates that the leaching of As with FeCl₃-citric acid from As³⁺ contaminated soil is a heterogeneous diffusion process. The coexisting ions, such as Ca²⁺, Al³⁺, SO₄^2- and PO₄^3-, 0.01~0.2 mol·L^-1 in concentration also had certain impacts on leaching of As. The higher the concentrations of the other coexisting ions, except for SO₄^2-, the better the leaching effect. The compound leachate is expected to have a bright prospect for its application thanks to its low cost and wide availability.