Chemically functionalized muliti-walled carbon nanotubes (MWCNTs)/vinyl ester resin (VE) nanocomposites were prepared. MWCNTs were first treated by H2SO4/HNO3 acid mixture, and then carboxylated MWCNTs were grafted of methacrylic acid glycidyl ester (GMA). Raman microscopy and Fourier transform infrared spectroscopy (FT-IR) analyses proved the effectivenss of acid-treatment and chemical functionalization. Furthermore, chemical functionalization did not greatly disrupt carbon nanotubes structure and Transmission electron microscopy (TEM) showed that there was a GMA thin layer on the MWCNTs surface, which contributes to the homogenous dispersion of MWCNTs in vinyl ester resin matrix and the CNTs-VE interfacial interaction. Thus the nanocomposites containing MWCNT-GMA possess larger storage modulus values as well as higher glass transition temperatures (Tg).