CaF2 nanoparticles doped with different Er concentrations were synthesized by a co-precipitation method. The phase compositions and morphology of the obtained Er:CaF2 nanoparticles were characterized by X-ray diffraction and transmission electron microscopy analysis. It was found that the size and shape of obtained CaF2 nanoparticles were modified through Er3+ doping. High quality Er:CaF2 transparent ceramics were fabricated by hot-pressed sintering method in a vacuum environment. The influence of Er3+ doping concentrations and sintering temperatures on optical transmission and microstructure of Er:CaF2 transparent ceramics were investigated. When doped with 5 mol% Er3+, the CaF2 ceramic sintered at 800 °C showed the best optical transmission, and for the 2 mm thickness sample, the optical transmission reached about 90% in the near-infrared spectral region. •Er:CaF2 nanoparticles were synthesized by coprecipitation method.•The size and shape of CaF2 nanoparticles were modified through Er doping.•Influence of Er content on transmissivity and microstructure was investigated.•Influence of temperature on transmissivity and microstructure was investigated.