The kinetics of oxidation-reduction reactions between N,N-diethylhydroxylamine (DEHAN) and plutonium(IV) in nitric acid solution have been studied by spectrophotometry at 25.2 °C. The initial rate equation of the reaction is -d[Pu(IV)]/dt=k0[Pu(IV)]2[DEHAN]1.26/[H+]2.53, where the rate constant of the reaction (k0) is (5.93±0.84).103 (mol/l)0.27 min-1. The complete rate equation and the rate constants of the reaction are also derived.