This paper introduces a blended membrane which is prepared by coagulation of sodium alginate and konjac glucomannan(KGM) in an aqueous solution, and studies the effect of different concentrations of KGM on sodium alginate films. The structural characterization of prepared blend film was implemented by scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FT-IR), and the optimum ratio was determined by comparing fracture elongation, moisture absorption and moisture retention. The results indicate that the two polysaccharide molecules, sodium alginate and KGM, in the blend membrane have a good compatibility. The surface of blend film is smooth and uniform. The addition of KGM can significantly improve the moisture absorption and moisture retention performance of sodium alginate film, and its mechanical performance is also improved to some extent. The ratio of sodium alginate and KGM is 3.2∶1.5. This paper introduces a blended membrane which is prepared by coagulation of sodium alginate and konjac glucomannan (KGM) in an aqueous solution, and studies the effect of different concentrations of KGM on sodium alginate films. The structural characterization of prepared blend film was implemented by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), and the optimum ratio was determined by comparing fracture elongation, moisture absorption and moisture retention. The results indicate that the two polysaccharide molecules, sodium alginate and KGM, in the blend The addition of KGM can significantly improve the moisture absorption and moisture retention performance of sodium alginate film, and its mechanical performance is also improved to some extent. The ratio of sodium alginate and KGM is 3.2: 1.5.