A naocrystalline layer (thickness of about 30 μm) was prepared by surface mechanical attrition treatment (SMAT) on commercial pure Ti, and the mean grain size on top-surface was about 30 nm. The SMAT Ti was then treated by immersing in H2O2 solution at 25 oC followed by calcination at 400 °C for 1 h. XPS was used to analyze the SMAT Ti structure layer by layer. The results show that obvious differences of the oxidation layer structure exist between SMAT Ti and CG (coarse grain) counterpart