Abstract: Fe-Sm-Yb-TiO₂ photocatalysts were synthesized by immersion method.With phenol as degradation target，the influencing factors of catalyst performance and the methods of improving the performance of catalyst were discussed.A preliminary discussion about the mechanism of co-doping improving photocatalytic activity of TiO₂ was also made by means of FE-SEM，XRD，and UV-Vis etc..Experiments showed that the most suitable conditions were as follow：when the mass concentration of phenol wastewater was 20 mg/L（normal temperature and pressure），the pH was 7，the dosage of catalyst was 2.5 g/L， the calcining temperature was 550 ℃，and the doping rate of Fe，Sm，and Yb were all 0.5%（mass fraction），the degradation rate was up to 90% under the UV light for 4 h.The modified titanium dioxide catalyst also demonstrated fine activity under the visible light.

Key words: titanium dioxide, photocatalyst, modification, characterization