Abstract: DPPH radical scavenging capacity was used as measuring indices of antioxidant activity In this research.Two- factor- at- a- time experiment was used to investigate the pulsed electric field( PEF) effects on antioxidant activity of MMCTN and the two factors were electric filed intensity( 5,10,15,20 k V / cm) and pulse frequency( 1800,2400 Hz).And the effects of retention time( 0,2 h) after PEF treatment on antioxidant activity were investigated.Then,mid- infrared spectroscopy( MIR) and circular dichroism spectrum( CD) were used to analyze the secondary structure changes of PEF treated MMCTN.The results showed that when the electric filed intensity was 10 k V / cm,pulse frequency was 2400 Hz and retention time was 2 h,the DPPH radical scavenging capacity was up to 94.14%± 0.13%.The MIR showed that the functional groups of PEF treated samples were changed and the CD indicated that α helices,β strands,β turn and random coil were interconverted.