We report the diffusion and stress coupling effect during oxidation. An analytical model is developed for the stress and diffusion coupling effect based on equilibrium relationship and diffusion equation considering for the stress effect. Compressive stress will generate during the oxidation due to the growth strain. This growth stress can modify the diffusion coefficient; therefore, the oxidation kinetics is also affected. The coupling effect reduces both the oxidation rate and the stress. The proposed model is applied to predict the oxidation evolution for SiC and its consistence with the experimental data demonstrates the theoretical analysis.