Abstract: To overcome the rigid and brittle defects in starch films,quaternized and octenylsuccinylated starch (QAS) was prepared and then mixed with poly(vinyl alcohol) (PVA) to prepare blend films. The crystallinity of the blend films was measured by X-ray diffractometer, and their surface morphology was observed with scanning electron microscope. The effects of QAS/PVA weight ratio and PVA structure on the mechanical properties of the blend films wereinvestigated. The results indicated that the degree of crystallinity of blend films was lower than that of pure QAS film. The elongation at break of blend films decreased gradually with an increase of QAS content,but their breaking strength decreased with the QAS content at first and then tended to increase. The blend films exhibitedminimum breaking strength at the QAS/PVA weight ratio of 50/50. Moreover, the breaking strength and elongation at break both increased with the increase of polymerization and alcoholysis degrees of PVA.