In this paper, three different methods were used to study the binding numbers and binding constants of chrome-azurol S (CAS) on bovine serum albumin (BSA), and almost same results were obtained. It is proposed that the concentration of CAS and pH of the solutions affect the binding mode of CAS and BSA. According to the theory of Forster non-radiative energy transfer, the binding sites of CAS on BSA are found. Taking advantage of fluorescence quenching, the reaction mechanism of CAS and BSA is explored.

Key words: SERUM ALBUMIN, CHROME AZUROLS, REACTION MECHANISM