Protein research is a hot spot at present, and has been involved in biology, medicine, food and other fields, and the development of nanotechnology has greatly promoted the research on protein. Simple, highly sensitive and highly selective detection is the key to the early diagnosis and treatment of major diseases, and it is also the direction with great market potential. However, the synthesis of fluorescent probes for many detection methods is complex and costly, and requires the use of toxic organic reagents. In this study, we detected bovine serum albumin (BSA) using a gold nanocluster (AuNCs@GSH) system with fluorescence quenching by chloramphenicol (CAP) as a probe. BSA could enhance the fluorescence intensity of AUNCs-GSH-CAP system, which was positively correlated with the concentration of BSA within a certain concentration range. This method has good selectivity and anti-interference, and the fluorescence effect is obvious. It has achieved a good linear relationship within 10-160 mol/L, and its detection limit is 0.1 mol/L, which has a good prospect for the rapid detection of proteins.