The denaturation of lysozyme was analyzed under two different denaturants (ethanol,dimethyl sulphoxide(DMSO)) using differential scanning calorimetry(DSC) and the isoconversional method.The lysozyme denaturation temperature tm increased slowly with the increase of the scan rate in the presence/absence of denaturants.The denaturants accelerated the denaturation of lysozyme and reduced the thermal stability of lysozyme.Ethanol has much more influence on the thermal stability of lysozyme than DMSO has.With the isoconversional method,the apparent activation energy of denaturation process did not keep constant at different conversion ratios (α) in the presence/absence of the two denaturants,but decreased with the increase of α,indicating that a simple reaction mechanism could not be used for explaining the denaturation process of lysozyme.The denaturation process was not standard reversible two states but multi-step process.The isoconversional method provides new opportunities in exploring the multi-step or one-step kinetics of protein denaturation.