Abstract: The recent progresses of codoped titania photocatalyst are reviewed. The photocatalytic degradation efficiency of titania can be further improved by codoping because of the synergy by doped elements. The mechanism of synergy of codoped titania are discussed from promoting visible light response，restraining recombination of photo-generated electrons and holes，increasing quantity of hydroxyl on the surface of catalyst，and other synergistic effects. The non-effective phenomena of synergy of codoped titania are introduced. Finally，the future research directions of codoped titania photocatalyst are also suggested.