Abstract: The kinetics of oxidation of malic acid by ditell uratoargentate(Ⅲ)ion was studied by spectrophotometry in alkaline medium. The reaction rate sho wed first order dependence on Ag(Ⅲ)and positive fractional order dependence on malic acid.kobs decreased with the increase in ［OH-］［TeO2- 4］ respectively. The active species and a plausible mechanism involving two-electron transfer have b een proposed .All the experimental phenomena can be explained by the rate equa tion derived from the mechanism. The rate constants of the rate-determining ste p together with the activation parameters have also been calculated.