Abstract: Three amide-based cellulose nanocrystals were synthesized, and the amide-based cellulose nanocrystals/ethylene-vinyl acetate copolymer (EVA) composite membrane materials were prepared by solution blending film-forming method. UV - visible spectrophotometer, electronic universal testing machine and water vapor permeability instrument were used to characterize the optical, mechanical and water vapor barrier properties of amide-based CNC/EVA composite films. The surface morphology of thermocompression treated EVA films was observed by atomic force microscopy. The results showed that the transmittance of EVA composite films can be decreased by adding three types of amide-based CNC, and the EVA composite film transmittance remained as high as 90% that the added amount of CNC up to 5%. Amide-based CNC can be dispersed in the EVA matrix more uniformly by a certain degree of thermocompression , so that EVA composite film transmittance can be increased by 2% ~3%. With the gradual increase of the content of CNC, three CNC/EVA film tensile strength are gradually increased, the WVTR values are reduced. Same amide-based CNC content, mechanical and water vapor barrier properties of Hexadecylamine modified cellulose nanocrystals (CNC-N16)/EVA films were better than that of dodecylamine and octylamine modified cellulose nanocrystals/EVA films.