Potassium persulfate (K2S2O8), as a widely used inorganic sulfur-containing peroxide in industrial fields, serves primarily as a bleaching agent, in film processing, and as an initiator for resin and rubber synthesis. However, there is currently a lack of efficient methods to distinguish it among various sulfur-containing inorganic compounds with multiple valence states. Bovine serum albumin-stabilized gold nanoclusters (BSA-Au NCs) were employed as a luminescent probe to achieve highly selective discrimination and sensitive detection of K2S2O8 in the presence of diverse sulfur-containing inorganic compounds. The fluorescence intensity of BSA-Au NCs exhibited continuous quenching with increasing K2S2O8 concentration, showing a good linear relationship within the concentration range of 5 nmol·L -1~10 μmol·L -1, with a detection limit as low as 1.3 nmol·L -1. Furthermore, a gel-based solid-phase device fabricated using BSA-Au NCs enabled highly selective visual sensing of K2S2O8. This gel-phase device demonstrates broad application potential for on-site rapid detection in practical scenarios.