A graded titania film was formed on chemically polished NiTi shape memory alloy (SMA) by a novel deposition-assisted advanced oxidation method in a modified Fenton’s reagent containing titanium tetrachloride and then characterized by SEM and XPS. The effects of the titania film on leaching of harmful Ni ions from the NiTi substrate in simulated body fluids (SBF) is assessed by inductively-coupled plasma mass spectrometry (ICPMS). The results indicate that a thick and dense titania film was successfully fabricated in this in situ advanced oxidation reaction assisted with an additional deposition process by the hydrolysis of titanium tetrachloride on NiTi. The titania film can dramatically reduces Ni leaching from NiTi. XPS depth profiles show that the film possesses a smooth graded interfacial structure that boost mechanical stability.