Poly(vinyl alcohol)/nano-silica (PVA/nano-SiO2) films were prepared through extrusion blowing with the addition of water and glycerin as plasticizer. The characteristic properties of PVA/nano-SiO2 films were investigated by differential scanning calorimetry, dynamic mechanical analysis, Haake torque rheometry, and atomic force microscopy (AFM). The results showed that the mechanical properties of PVA/nano-SiO2 were improved dramatically. The tensile strength of the nanofilms increased from 62 MPa to 104 MPa with loading 0.3 wt % nano-SiO2 and the tear strength was improved from 222 KN/m to 580 KN/m. The crystallinity of the films loaded with 0.4 wt. % nano-SiO2 decreased from 32.2% to 21.0% and the AFM images indicated that the amorphous region of nanofilms increased with increasing nano-SiO2 content. The storage modulus and loss modulus increased to two and nearly three times with 0.3 wt % nano-SiO2 loading. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013