The gelatin-pullulan composite films were prepared. Then the properties of composite films were determined to provide a direction to evaluate the performance of hard capsules, optimize the ratio between capsule materials， and reduce the brittleness and water vapor permeability (WVP). The compatibility between gelatin and pullulan was characterized by light transmittance, Fourier transform infrared spectroscopy and scanning electron microscopy. The results indicated that it could be used for the blending modification of gelatin hard capsules when the glycerol addition was 10% (dry basis percentage), and the mass ratio between gelatin and pullulan was 91. The WVP of the composite films, prepared by the above conditions, was reduced by 26% compared with that of the gelatin films. The elongation at break was 1.19 times higher than the level of gelatin films in low humidity environment. There was good compatibility between the molecules of gelatin and pullulan in the composite films, which could explain the improvement of mechanical stability, and the reduction of WVP.