Abstract: In this work, using Eu³⁺ embedded tungsten-oxygen cluster (compound 1) as the fluorescent probe material, the rapid and sensitive fluorescence detection of heavy metal Cr³⁺ ions in aqueous solution by compound 1 has been systematically studied. The selectivity, anti-interference ability and detection limit of compound 1 for fluorescence detection of Cr³⁺ ions in water were characterized and analyzed by steady-state transient fluorescence spectrometer. The results showed that compound 1 exhibited a rapid and sensitive fluorescence quenching response to heavy metal Cr³⁺ ions with strong anti-interference ability. The calculated value of quenching constant (1.41×10⁸ L·mol⁻¹·s⁻¹) was far lower than the maximum scattering collision quenching constant (2.00×10¹⁰ L·mol⁻¹·s⁻¹), which showed that compound 1 exhibited a rapid and sensitive fluorescence quenching response to heavy metal Cr³⁺ ions. Fluorescence detection results of compound 1 in the aqueous solution containing different cations and anions showed that compound 1 had strong anti-interference ability for fluorescence detection of Cr³⁺ ions in aqueous solution. The calculated results indicated that detection limit of compound 1 for Cr³⁺ ions in aqueous solution was 4.21×10⁻⁷ mol/L, which showed that compound 1 had a good detection effect on Cr³⁺ ions in water environment. This study was supposed to provide a sensitive and reliable method for the fluorescence detection of heavy metal Cr³⁺ ions in water.