The united model, which is applicable to the premixed and diffusion flame using of author's premixed combustion model. To verify the accuracy of the model, the turbulent opposed diffusion flame presented by Mastorakos was numerically simulated, as an example of a turbulent diffusion flame. The overall thickness of temperature and mass fraction profiles were in good agreement with experimental data. These comparisons with the experimental data and this agreement confirmed the proposed unified model was able to accurately simulate diffusion flame under the certain flame stretch.