TiO2 thin films were prepared by DC reactive magnetron sputting using high putity Ti as the targets and high O2 as the reaction gas. The influence of the oxygen flow on the film crystalline orientation,surface morphology and optical properties were studied. The results show that the TiO2 films is anatase TiO2 (101) preferred orientation; when the oxygen flow rate is small, the film also contains metal Ti(100); when the oxygen flow was larger, the films containing TiO2(101) and (004) into a polycrystalline state;the roughness and particle size of the films increases with oxygen flow; film visible- near-infrared bands have a higher transmission rate and the absorption peak increases with the oxygen flow in the 400~1 100 nm redshift; when oxygen flow 5 sccm, the average transmission is largest.