Tm3+ doped Na5Lu9F32 single crystal with high optical quality was grown by an improved Bridgman method.The Judd-Ofelt intensity parameters Ωt (t=2,4,6) were calculated according to the measured absorption spectra and physical-chemical properties of the obtained Na5Lu9F32 single crystal.The stimulated emission cross-section of the 3F4→3H6 transition (~1.8 μm) is 0.35× 10-20 cm2 for Tm3+ doped Na5Lu9F32 single crystal.The emission spectra under the excitation of 790 nm laser diode (LD) and fluorescence lifetime at 1.8 μm were measured to reveal the fluorescence properties of Tm3+ doped Na5Lu9F32 single crystal.The research results show that the Tm3+ doped NasLu9F32 single crystal has larger stimulated emission cross-section compared with other crystals.All these spectral properties suggest that this kind of Tm3+doped Na5Lu9F32 crystal with high physical-chemical stability and high-efficiency emission at 1.8 μm may be used as potential laser materials for optical devices.