Oxidation of metals is a complex reaction in which mechanical and chemical phenomena occur. A dynamic and macroscopic model is developed in order to simulate oxidation kinetics of a metal. It includes the stress/diffusion coupling in the bulk and the interfacial phenomena at metal/oxide interface. Its application to the Zr/ZrO2 system shows the important role of stress Field distribution in oxide on kinetic behavior. According to the sign of stress gradient in the oxide scale, the oxidation rate can speed up or slow down. The calculated kinetic curves could be fitted using a k(p.t)(1/n) law where n and k(p) vary all over the process, like for the experimental kinetic curves.