Abstract: Poly(ethylene glycol) (PEG) was grafted onto multiwalled carbon nanotubes (MWNTs) by atom transfer radical polymerization, and its structure and performance of MWNTs-PEG was investigated with scanning electron microscopy,transmission electron microscopy,infrared spectroscopic and thermogravimetric analysis. The POM/MWNTs-PEG composite films were prepared by heat compression, and their crystallizations behaviors and non-isothermal crystallization kinetics were studied by differential scanning calorimetry using Jeziorny's and Mo's methods. The effect of MWNTs-PEG on the performance of composites was also investigated. The results indicated that PEG was successfully grafted onto MWNTs, and the presence of MWNTs-PEG generated a heterogeneous nucleation effect on the crystallization of POM. As a result, the crystallization temperature and crystallization rate were improved, and the crystallization time was shortened accordingly. The crystallization kinetic investigation indicated that the crystallization rate constant of POM/MWNTs-PEG composites increased but the F(T) value decreased. Moreover,the effective crystallization activation energy was reduced, suggesting a promoting effect of MWNTs-PEG on the crystallinity of POM.