Performic acid (PFA) is an oxidant used in chemical processing, synthesis and bleaching. The macro kinetic models of synthesis, hydrolysis and decomposition of PFA were investigated via formic acid-autocatalyzed reaction. It was found that the intrinsic activation energies of PFA synthesis and hydrolysis were 75.2 kJ.mol(-1) and 40.4 kJ.mol(-1) respectively. The observed activation energy of PFA decomposition was 95.4 kJ.mol(-1). The experimental results indicated that the decomposition of PFA was liable to occur even at the ambient temperature. Both the spontaneous decomposition and the radical-introduced decomposition contributed to the decomposition of PFA.