Bovine　Serum　Albumin　(BSA)　was　used　as　a　target　protein　to　study　the　structure　change　through　tyrosine　nitration　by　peroxynitrite.　The　correlation　between　BSA　nitration　and　the　structure　change　was　established　The　results　show　that　the　nitration　of　BSA　by　simulating　the　situation　in　vivo　(continuous　infusion　of　ONOO-)　is　two　times　efficiency　than　infusion　ONOO-at　one　time.　The　nitration　by　peroxynitrite　lead　to　a-helix　structure　reduced　and　(1-sheet　structure　increased,　which　make　significant　changes　of　BSA　backbone.©　2011　IEEE.