Abstract: <FONT face=Verdana>Modification technology of nano-TiO2 coated on surface of purified diatomite by hydrolyzation-precipitation method was studied.Synthesized compound material was characterized by SEM,EDX,and XRD etc..Photocatalytic activities of the obtained samples were examined by degrading decolorization tests of Rhodanmine B solution.Analysis and test results showed that the SiO2 mass fraction of purified diatomite reached more than 90% and it′s a preferable carrier material;a compact film of TiO2 was coated on surface of the purified diatomite;crystal of TiO2 was anatase,and average crystal size was 10 nm;the synthesized compound material had good photocatalytic activity,and its decolorizing rate for Rhodanmine B solution was obviously higher than the nano-TiO2(P25) made by Degussa Company in Germany.&nbsp; </FONT>