In this paper, the reaction kinetics of Potassium Ferrate (VI) with L-alanine was studied spectrophotometrically. The reaction was determined under alkaline condition at the temperatures rang of 298.2K-318.2K and the pH rang of 9.12 -10.27. All data was obtained from the pseudo-first order reaction. It was found that the reaction is a first-order for reactant. The observed rates constants (k_obs) increased with the increase of [reductant], whereas the kobs decreased with the increase of [OH^-]. The reaction is negative fraction order with respect to [OH^-]. A plausible mechanism involving a slow reaction as the rate-controlling step is proposed and the rate equations derived from the mechanism can explain all the experimental results. The rate constants of the rate-controlling step and the thermodynamic activation parameters at 298.2K were also calculated.