TiO2　powders　co-doped　with　Gd3+　and　Zn2+　were　prepared　by　a　sol-gel　method.　Effect　of　Gd3+　and　Zn2+　co-doping　on　the　phase　composition,　surface　morphology,　photocatalytic　activity　of　TiO2　powder　samples　was　investigated.　The　photocatalytic　activity　was　evaluated　via　the　photodegradation　of　methyl　blue　dye　in　solution.　The　results　show　that　the　obtained　sample　is　a　mesoporous　material　with　anatase　phase　structure.　The　nanocrystalline　TiO2　co-doped　with　Gd3+　and　Zn2+　exhibits　a　synergistic　effect,　which　enhances　the　photocatalytic　activity　of　TiO2　powder.　Two　dopants　of　Gd3+　and　Zn2+　in　nanocrystalline　TiO2　have　different　effects　on　suppressing　the　recombination　of　photogenerated　electrons　and　holes,　namely,　Gd3+　serves　as　an　electron　trap　and　Zn2+　serves　as　a　hole　trap.　TiO2　powder　co-doped　with　0.5%Gd3+　and　0.3%Zn2+　has　the　optimum　photocatalytic　activity.　The　photodegradation　efficiency　is　99.5%　after　40　min　ultraviolet　irradiation.　Compared　to　TiO2　mono-doped　with　either　0.5%Gd3+　or　0.3%Zn2+,　the　photodegradation　efficiency　of　TiO2　powder　co-doped　with　0.5%Gd3+　and　0.3%Zn2+　is　increased　by　11.5%　and　9.3%,　respectively.　©　2015,　Chinese　Ceramic　Society.　All　right　reserved.