Thick film resistor is increasingly applied to electrothermal films, but oxidation resistance of thick film resistor on the surface of porous ceramic substrate was seldom studied. The oxidation resistance of stainless steel thick-film resistor at 400 ℃, 500℃, 600℃ and 700 ℃ was studied by doping TiB2 ceramic powder. The phase structure and microstructure of the thick-film resistors not doped with and doped with TiB2 were studied by means of XRD, SEM and EDS. Oxidation kinetics curves of the two thick-film resistors conform to the parabolic law ((Δw)n=kt). The index n of the two thick-film resistors was 4, and the oxidation rate constant (K1) of TiB2-doped thick-film resistors was 1955.8 g4m-8h–1 at 400℃, while the oxidation rate constant (K2) of TiB2-free thick-film resistors was 4694.9 g4?m–8?h–1 since higher compactness of TiB2-doped thick-film resistors contributed to higher oxidation resistance. The index n of the two thick-film resistors was 2 at the temperature above 500 ℃, and the oxidation rate constant of TiB2-doped thick-film resistors was higher than that of the TiB2-free one, since gaps were present in the film as a result of TiB2 oxidation. The oxidation resistance of thick-film resistors reduced in case of severe oxidation in the film (oxidation products were mainly (TiO2, B2O3, Fe2O3 and (Fe0.6Cr0.4)2O3). In stainless steel thick-film resistors, the doping of TiB2 can improve oxidation resistance of the film at 400 ℃, but damage oxidation resistance of the film at temperature above 500 ℃.