Abstract A new kinetic model is proposed to describe the isothermal oxidation of metals and alloys in the form of sphere, flat plate and fiber shape with considering oxidation induced volume change or Pilling–Bedworth Ratio. The effects of temperature, oxygen partial pressure, particle size, sample shape on the oxidation reaction fraction are analyzed in the model through a physical meaning explicit function. The oxidation experimental data of zinc powders and plates were used to check the model. The results show that the calculated curves agree well with the experimental data and the model can give a good theoretical prediction. All of these will be useful for studying the oxidation of intermetallics either.