Polyvinyl alcohol (PVA)-sodium alginate (SA)/Na-rectorite (Na+REC) nanofilm were prepared by water solution processing. The structure and intercalation mechanism were analyzed by using XRD and TEM. The transmittance, mechanical properties, gas or liquid barrier properties as well as thermal properties were systematically investigated. It was found that introduction of a small amount of PVA can show evident positive effect on intercalation; the intercalation effect and properties of composites of 10% PVA are optimal; the tensile strength, elongation at break for PVA10-SA/Na+REC2 are 42.2%, 35.4% higher than those of SA/Na+REC2, respectively. The weight lose of the composite sample in 36 ℃ to 230 ℃ range is 3.48% lower than that of SA/Na+REC2 and the film have excellent transmission of light and gas or liquid barrier properties.