The effects of calcium fluoride （CaF₂） doping on the optical and physical and chemical properties of Ytterbium fluoride （YbF₃） materials were studied. Pure YbF₃ thin films and YbF₃ thin films doped with different proportions of CaF₂ were deposited by electron beam and thermal evaporation， respectively. The characteristics of single layer were measured by spectrometer， stress measurement system， X-ray Diffraction （XRD）， Atomic Force Microscope （AFM） and other measuring devices. The optical constants were fitted by the classical Lorentz oscillator model. The results show that the single-layer film with better optical and physical and chemical properties is obtained by electron beam deposition， in the condition of 1% CaF₂ doping. A long-wave infrared anti-reflection multi-layer sample was designed and fabricated and its spectrum and reliability test were carried out. The results show that its transmittance in the long-wave infrared region is as high as 99%， and the reliability meets the requirements of space application.