Abstract: Chitosan film and sodium alginate composite film were prepared by using edible raw materials. Chitosan film was prepared by dissolving chitosan in 4% acetic acid solution (V/V), adding 1% glycerin (V/V) as plasticizer and 0.1% liquid paraffin as release agent, and then drying at 70 ℃ for 7 h. The prepared chitosan film was characteristics of 100 nm in thickness, 240.0 kg/cm2 in tensile strength and 89.2% light transmittance. The optimal formula for sodium alginate composite film determined by orthogonal array design was 8 mg/mL sodium carboxy methyl cellulose, 12 mg/mL sodium alginate, 8 mg/mL gelatin, 2 mg/mL AGAR and 8% (V/V) glycerin. The resulting sodium alginate composite film was characteristics of 0.070 mm in thickness, 116.7 kg/cm2 in tensile strength and 71.6% light transmittance. The results of performance tests showed that both kinds of film exhibited an excellent resistance to oil and oxidants as well as high flexibility and thermoplasticity.

Key words: chitosan composite film, edible, processing technology, fresh-keeping film