A novel fluorescent H2S probe (LODNBS) composed of 2,4‐dinitrobenzenesulfonyl (DNBS) units was designed and synthesized. The DNBS units not only blocked PET and ICT effects, but also triggered H2S‐mediated thiolysis to cause the fluorescence changes. Probe LODNBS performed excellent sensitivity and selectivity for H2S, strong fluorescence enhancement (65‐fold), low detection limit (72 nM) and real‐time response (within 5 min). The sensing mechanism of LODNBS towards H2S was proposed and verified by ESI‐MS and 1H NMR analysis. Under a UV lamp, the fluorescence color changes could be easily detected by the naked eye. In addition, the probe LODNBS could track H2S in red wine samples with high accuracy and good recovery, and has practical value in food analysis.