Abstract: From the results of the electrophoresis experiments with different concentrations of Na2HPO4 and NaH2AsO4, and different ratios between the two salts, it was concluded that the specific adsorption of phosphate and arsenate in laterite soil reduced significantly the Zeta-potential and TEP of the colloid, but the influence of the latter was larger than that of the former. Therefore, behaviours of the specific adsorption of phosphate and arsenate on surface charge of laterite soil were similar.