TiO₂ film is an important photo-induced catalyzer and it also presents hyper hydrophilicity properties. However the applications of this material are greatly limited due to its low efficiency under visible light. A promising way to improve its photocatalytic effect is to dope with some nonmetal elements. The visible light absorption and hydrophilicity of N-doped TiO₂ film on quartz substrates prepared by R.F magnetron sputtering are obtained,with the working gas of Ar/N2,the samples were post-treated by annealing under different temperatures in nitrogen atmosphere. The structure,doping,surface morphology and optical properties of undoped and N-doped TiO₂ films by means of XRD,XPS,SEM and UV-vis spectra were analyzed. The XRD results indicated that TiO₂ anatase is formed around 600 ℃ and N atoms are doped in TiO₂ crystal lattice as shown in XPS studies. For the UV-vis analysis of N-doped samples,it is found that a dramatic red drift occur in the absorbance spectra compared with that of TiO₂ thin films,which means a higher visible light catalysis activity. The water contact angle measurement of the annealed samples under visible light radiation for 30 min showed excellent hydorphilicity with a water contact angle less than 10°.