Tm³⁺doped Na₅Lu₉F₃₂single crystal with high optical quality was grown by an improved Bridgman method. The Judd-Ofelt intensity parameters Ω_t(t=2, 4, 6) were calculated according to the measured absorption spectra and physical- chemical properties of the obtained Na₅Lu₉F₃₂single crystal. The stimulated emission cross-section of the ³F₄→³H₆transition (~1.8 μm) is 0.35×10^-20cm²for Tm³⁺doped Na₅Lu₉F₃₂single 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 Na₅Lu₉F₃₂single crystal. The research results show that the Tm³⁺doped Na₅Lu₉F₃₂single crystal has larger stimulated emission cross-section compared with other crystals. All these spectral properties suggest that this kind of Tm³⁺doped Na₅Lu₉F₃₂crystal with high physical-chemical stability and high-efficiency emission at 1.8 μm may be used as potential laser materials for optical devices.