Nylon66／montmorillonite composites with 2.5 wt％ and 4.5 wt％ clay loading have been prepared by melt process．Non-isothermal and isothermal crystallization behavior of the samples has been investigated by dynamic scanning calorimeter (DSC)

compared with that of pure nylon66．The results have shown that the presence of montmorillonite particles displays a high propensity to nucleate nylon66 crystallization and enhances the crystallization rate of nylon66．But the strong interaction between nylon66 and montmorillonite restricts the motion of nylon macromolecular segments

which thus leading to the increase of the activation energy of crystallization．The behavior of crystallization with the different filler contents has changed slightly．And the temperature range from 228℃ to 234℃ is an insensitive-temperature region of crystallization for composite．Liu’s method is suitable for investigating the non-isothermal process

but Ozawa’s method is not．