The work aims to analyze the relationship between mechanical and optical properties of TiO2 films by comparing the variation of TiO2 films at different sputtering power and oxygen tension. TiO2 films were deposited on K9 glass substrate by virtue of DC reactive magnetron sputtering method at room temperature. UV-Vis spectrophotometer and Ellipsometer were used to characterize the optical properties of the TiO2 films, and their mechanical performance was tested by utilizing nanoindentation technology. It showed that the optical refractive index of the TiO2 films was positively correlated with their nano hardness and elastic modulus within a given range of process parameters. Film refractive index, nano hardness and elastic modulus increased while optical band gap of the fims decreased as the sputtering power increased. Meanwhile, during the deposition process, the O2 flow rate had significant effects on optical and mechanical properties of the TiO2 films. When the O2 mass flow rate reduced from Q(Ar)/Q(O2)=5/1 to 10/1, the refractive indexes of the films decreased while the optical band gap increased. However, when the O2 mass flow rate reduced to Q(Ar)/Q(O2)=20/1, the refractive indexes of the films increased and exceeded that obtained at Q(Ar)/Q(O2)=5/1, and the band gap decreased and was lower than that obtained at Q(Ar)/Q(O2)=10/1. Beyong that, the nano-hardness and elastic modulus of the films continuously decreased as the O2 mass flow rate decreased. The refractive index and optical band gap of the TiO2 films deposited by magnetron sputtering are inverse correlated. Furthermore, the optical band gap is correlated with mechanical properties of the films prepared at certain O2 mass flow only.