In this paper, a salamo-based copper( ii ) complex probe L-Cu 2+ was synthesized, which combined with copper( ii ) ions to form L-Cu 2+ for the detection of S 2− and had a good fluorescence chemical response. Through spectral analysis, we found that S 2− could be identified with high sensitivity and selectivity in the presence of various anions and could be used for the detection of S 2− by the naked eye. With the addition of S 2− , the solution color changed from colorless to bright yellow. UV absorption, fluorescence and other characterization methods were carried out, and the mechanism of action was determined. In addition, we performed a visual inspection of H 2 S gas, and the probe L-Cu 2+ could detect S 2− in the gas molecules, revealing its potential application value in biology and medicine. A highly sensitive and selective salamo-based copper( ii ) complex probe, L-Cu 2+ , was synthesized; it could be used for the detection of S 2− by UV and fluorescence spectroscopies. And it also could detect S 2− in gas molecules.