Abstract: Ion beam sputtering is one of the best important technologies for preparing Ta2O5 thin films. The correlation properties of Ta2O5 thin films and preparative parameters(substrate temperature, ion beam voltage, ion beam current and oxygen flow) were systemic researched by using the orthogonal experiment design method. The Ta2O5 thin films properties(refractive index, extinction coefficient, deposition rate, stress and inhomogeneity of refractive index) were studied. The refractive index, extinction coefficient, physical thickness and inhomogeneity of refractive index were measured by multiple wavelength curve-fitting method from the reflectance and transmittance of samples. The stress of thin film was measured by elastic deformation of thin film-substrate system. An experimental design strategy used substrate temperature, ion beam voltage, ion beam current, and oxygen flow as the variables. The experimental results indicate that the temperature of substrate is key influence parameter on Ta2O5 thin films properties and other preparative parameters are correlation with specific thin films properties. The results can be used to select the proper preparative parameters for preparing Ta2O5 thin films with different applications.