Several kind of wide band-gap fluoride materials are studied to determine optical constants of fluoride films in deep ultraviolet(VUV) to ultraviolet(UV). High-refractive-index materials LaF3,NdF3,and GdF3 and low-refractive-index materials MgF2,AlF3,and Na3AlF6 single thin films are deposited by a resistive-heating boat on JGS1 and single crystal MgF2 substrates respectively at different deposited rates and specific substrate temperatures.Transmittances of all fluoride thin films are measured through a commercial spectrometer in the ambient atmosphere and wavelength regions from 190 nm to 500 nm,and measured through synchrotron radiation under vacuum in the wavelength regions from 120 nm to 300 nm.The optical constants of these materials are determined by a envelope method and a simulated annealing method,which matches the calculated and measured values of the transmittance.Measured results indicate that the refractive indexes are about 1.77~1.89 at 157 nm for LaF3,NdF3,and GdF3 single layer films,and are about 1.44~1.48 at 157 nm for MgF2,AlF3,and Na3AlF6 single layer films. Experiments show also that these high and low index materials can be composited to material pairs to design and manufacture the cost-effective,mechanically and optically stable optical coatings in 120 nm to 500 nm for new thin devices.