The corn nano-starch/cellulose nanocrystalline(CNC) composite film was prepared by casting method with corn nano-starch as substrate, glycerol as plasticizer and CNC as reinforcing agent. Film forming substrate and drying temperature have influences on film formation of nano-starch, and PVC matrix plate is better. When drying temperature is 25 ℃, the film forming is smooth and good. The effects of corn nano-starch, glycerol and CNC content on the strength properties of nano-starch/CNC composite film were investigated by single factor, and three factors and three levels orthogonal test were also carried out. Orthogonal optimization study showed that the tensile strength of composite film was: CNC > glycerol>corn nano-starch. The optimum results of orthogonal experiment were as followed: CNC 2%, glycerol 8% and corn nano-starch 10%, and the tensile strength of composite film can be reached 20.18 MPa. FTIR analysis also showed that corn nano-starch, glycerol, CNC were mixed evenly, and a homogeneous and stable nano-starch/CNC composite film was formed. The corn nano-starch/CNC composite film has a good application prospect in the field of edible packaging of food and drugs.