The invention discloses a fluorescence detection method for antiepileptic drug tiagabine hydrochloride (TGB). Through the study of the interaction of dye perylene diimide derivatives (PDI), human serum albumin (HSA) and tiagabine hydrochloride (TGB), we found that the fluorescence of PDI can be quenched by HSA, and our research It shows that PDI binds at site II of HSA, and TGB can compete for binding at site II of HSA, so that PDI is competed from site II of HSA, thereby realizing fluorescence recovery. Based on this, the present invention proposes a fluorescence detection method for TGB, which uses PDI‑HSA as a probe to realize fluorescence recovery under the action of TGB, so as to detect TGB. The method of the invention has the advantages of original innovation, simple detection process, mild experimental conditions, high sensitivity, good selectivity, fast detection time, low detection limit, etc., and has good social value and application prospect.