The interaction between amine terminated G3.0 PAMAM dendrimers and bovine serum albumin (BSA) under physiological condition was studied by fluorescence spectroscopy. Our experiments demonstrated that the fluorescence intensity of BSA decreased after the addition of G3.0 PAMAM dendrimers and the quenching mechanism was suggested as static quenching according to the Stern-Volmer equation The binding constant of G3.0 PAMAM dendrimers with BSA was calculated to be 1.067 +/- 0.025 L x mmol(-1). At the same time, synchronous fluorescence and red edge excitation shift (REES) were adopted to review the conformational changes of BSA influenced by G3.0 PAMAM dendrimers, which provides important significance for clinical medication And the results indicated that G3.0 PAMAM dendrimers can change the conformation of BSA. Furthermore, this article also examined the influence of pH and ionic strength on the interactions, from which we can conclude that electrostatic interaction played major roles in the binding process. In conclusion, the fluorescence method is a highly sensitive and convenient way to study intermolecular interaction. Further investigation in this field will provide more important information for understanding the pharmacological effects and toxicities of drugs in human body.