The oxidation kinetics of metals/alloys at elevated temperatures is essential to the corrosion-life prediction of the structural materials in advanced energy systems. The growth of oxide film on a metal surface typically involves coupling of chemical reaction and diffusion of charged point defects. A phase-field model is developed to address the essential physics during metal oxidation over a continuous range of time and film thickness. The model is able to reproduce the classic Deal-Grove model with respect to the linear-parabolic transition. In particular, the model reproduces Wagner’s theory in the thick film limit and predicts a deviation from the Wagner-parabolic growth when the oxide film thickness is on the order of Debye length. The essential characteristics of electric field developed in an oxide film during high temperature metal oxidation and some other progresses in terms of realistic oxidation modeling will also be discussed.