Abstract: Sulfane sulfur species in the reactive sulfur species family include hydrogen polysulfides (H₂S_n, n ≥2), which play an essential role in physiological regulation and signal transduction. As a redox pair of H₂S, H₂S_n can be produced through oxidation or enzyme reaction and regulate protein interaction and enzyme activity.Research has revealed that H₂S_n, with higher efficiency of protein S-sulfhydration than H₂S, may be responsible for some physiological functions previously attributed to H₂S.Therefore, real-time detection of H₂S_n is crucial for studying its physiological activity and the relationship between H₂S and H₂S_n.Traditional detection methods, such as mass spectrometry, are not suitable for living organisms as they require tissue cell disruption.Instead, fluorescence probes are often used for in situ real-time detection due to their high sensitivity and specificity and low biological toxicity.This review summarizes the physiological regulatory activity of H₂S_n, as well as the design strategy, response mechanism, fluorescence characteristics, and biological applications of H₂S_n fluorescent probes based on the structure of the response group, with a prospect of the challenges and developments in this field.