The thermal and flame retardancy properties of high-density polyethylene (HDPE)/ ethylene vinyl-acetate copolymer (EVA)/ fullerene C60 nanocomposites were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and cone calorimetry with C60 loading varied from 0.5 to 2% by weight. Dispersion of C60 in HDPE/EVA blends was characterized by transmission electron microscopy (TEM). TGA and DSC results showed that the presence of C60 could remarkably enhance the thermal property and cone calorimeter measurements indicated that C60 could to some extent reduce the flammability of HDPE/EVA, with a significant reduction in peak heat release rate and a much longer time to ignition. Furthermore, the larger the loading level of C60, the better the flame retardancy of HDPE/EVA/C60 nanocomposites.