The aim of this study was to modify the surfaces of titanium dioxide (TiO2) nanoparticles with different precursors of sulfur and phosphorus dopants. The modified TiO2 were prepared by adding the dopant precursor during sol-gel process with molar ratio of non-metal elements: Ti = 0.03. The prepared modified TiO2 were used as a support for platinum catalysts for CO oxidation reaction. The results suggested that the presence of trace sulfur or phosphorus in TiO2 could improve the catalytic activity of Pt catalysts. The insertions of sulfur and phosphorus into the TiO2 lattice promoted the weak adsorbed oxygen species and resulted in catalytic activity improvement in CO oxidation. The modified TiO2 supported Pt catalysts using methyl sulfoxide and triethyl phosphate as precursor sources of sulfur and phosphorus exhibited the highest activity in the CO oxidation reaction with light-off temperature of 77 °C and 59 °C, respectively. The optimum molar ratio of S:Ti for methyl sulfoxide precursor was 0.05 and that of P:Ti for triethyl phosphate precursor was 0.03.