This study showed that the increasing of ball milling time caused a beneficial surface chromium enrichment of AISI 304 stainless steel. In addition, grain size decreased with the increasing of ball milling time. The electrochemical results showed that oxidation reaction transition of Cr2O3 to CrO3 was significantly inhibited by surface enriched chromium, which improved corrosion resistance of AISI 304 stainless steel. Moreover, higher surface enriched chromium reduced acceptor concentration in passive film, which also improved corrosion resistance of AISI 304 stainless steel. Moreover, more chromium oxides improved corrosion resistance of AISI 304 stainless steel in borate buffer solution. (C) 2017 Elsevier B.V. All rights reserved.