Abstract: A batch incubation test was conducted to study the characteristics of arsenic (A s) and phosphorous (P) adsorption-desorption as well as the effects of the comp etitive adsorption of the two elements on their translocation and activation in three kinds of purple soil, the typical soil in Three Gorges Area. In the test a cid, neutral, and calcareous purple soils, As and P adsorption-desorption had t he similar characteristics, with their isothermal adsorption conformed to Langmu ir and Freundlich equations. The maximum adsorption of As in the acid, neutral, and calcareous purple soils was 14286, 12500, and 11111 mg·kg-1, an d that of P was 3226, 3571, and 4348 mg·kg-1, respectively. The ads orption of As and P was fast at the beginning and slowed down then. The kinetics corresponding to the fast process was of first order, and that to the slow proc ess was of Elovich type. The mechanism for the fast process might be exchange ad sorption, and that for the slow process might be specific adsorption. When the A s and P coexisted, the adsorption rate and quantity of P increased while those o f As decreased, implying that the existence of As could promote the adsorption o f P in purple soil, while the existence of P would restrain the adsorption of As.