A series of Tb3+ doped CaF2 phosphors with different Tb3+ concentrations are synthesized by the microemulsion system composed of cetyltrimethyl ammonium bromide (CTAB), n-butyl alcohol, cyclohexane and water under the hydrothermal environment. The crystal structure, particle size, morphology and composition of the fluorescent powder are represented by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). Photoluminescence excitation spectra, emission spectra and luminescence decay curve are used to characterize the fluorescence properties of phosphors. The experimental results show that XRD test results are in good agreement with the cubic phase of CaF2; SEM study shows that the CaF2Tb3+ phosphors are spherical-like shape and their particle sizes are about 30 nm. The optimal doping amount of substance concentration of Tb3+ in phosphors is 6%. Photoluminescence emission spectra indicate that the CaF2Tb3+ phosphors emit strong green light with 259 nm light excitation. The excellent luminescence properties make CaF2Tb3+ a new promising green phosphors for fluorescent labeling application.