Trivalent　chromium　Cr(III),　which　was　originally　considered　to　be　innocuous　as　a　nutriment,　has　been　suspected　to　induce　some　abnormalities　in　human　body　recently.　In　the　present　work,　the　effects　of　Cr(III)　on　the　structural　state　of　BSA　were　comprehensively　investigated　through　a　series　of　appropriate　methods　in　combination,　including　X-ray　photoelectron　spectroscopy　(XPS),　fourier　transform　infrared　spectroscopy　(FTIR),　circular　dichroism　(CD),　UV-vis　absorption,　synchronous　fluorescence,　fluorescence　lifetime　analysis,　resonance　light　scattering　(RLS),　dynamic　light　scattering　(DLS)　and　excitation-emission　matrix　spectroscopy　(EEMS)　methods.　XPS　accurately　described　the　binding　activity　of　Cr(III)　with　protein　C,　N　and　O　atoms.　The　structural　analysis　according　to　FTIR　and　CD　methods　showed　that　the　Cr(III)　binding　altered　BSA　conformation　with　a　major　reduction　of　alpha-helix.　RLS　and　DLS　analyses　demonstrated　that　the　presence　of　Cr(III)　with　low　concentration　could　induce　the　aggregation　structural　changes　of　BSA.　UV-vis　absorption,　EEMS　and　synchronous　fluorescence　suggested　that　the　interaction　between　Cr(III)　and　BSA　induced　a　slight　unfolding　of　the　polypeptide　backbone　and　altered　the　microenvironments　of　Trp　and　Tyr　residues　in　BSA.　This　research　is　helpful　for　understanding　the　structure-function　relationship　involved　in　metal　ion-protein　bioconjugate　process.　(C)　2014　Elsevier　B.V.　All　rights　reserved.