Peroxynitrite　can　be　highly　efficient　catalyzed　to　harmless　products　with　a　turnover　frequency　34.5　s(-1)　by　micromolar　concentration　of　water-soluble　iron　porphyrin,　5,　10,　15,　20-tetralcis-(4-carboxyphenyl)-porphyrin-F-(III)-chloride　(T(p-COOH)(PPFeCl)-Cl-(III)).　Then　we　used　spectroscopic　and　kinetic　to　study　its　decomposition　mechanism　and　rate　in　bionic　environment　(25　mM　sodium　bicarbonate).　The　data　reveal　that　this　catalytic　reaction　is　a　recyclable　reaction.　Peroxynitrite　is　decomposed　to　nitrate　(NO3-)　and　nitrite　(NO2-)　through　forming　[oxoFe((IV))](+)　intermediate.　Moreover,　the　[oxoFe((IV))](+)　intermediate　is　reduced　back　to　the　starting　porphyrin.　It　is　noted　that　the　oxidized　iron　porphyrin　can　be　reduced　by　the　reducing　agent　in　the　solution.　In　addition,　we　also　find　the　catalytic　rate　constant　is　higher　in　the　presence　of　sodium　bicarbonate　than　the　absence　of　sodium　bicarbonate.　They　are　1.26　x　10(6)　M-1　s(-1)　and　1.17　x10(6)　M-1　s(-1),　respectively.