The chitosan and gelatin blends (CGB) were prepared with the gelatin content from 0% to 100%.The compatibility of the blends was discussed by calculating the interaction parameter and by detecting the phase structure with UV VI spectrum and PCM microscopy.As a result the minus interaction parameter and the homogenous structure certified the compatibleness of chitosan and gelatin.The mechanical properties of CGB were also determined.CGB film showed a plastics like stress strain curve in dry state and a rubber like stress strain curve in wet state.The tensile stress of CGB decreased with the increasing of felatin content;the elongation at break decreased with the increasing of gelatin content in dry state but they were higher then that of both chitosan and gelatin except from CGB-90 in wet state.Infrared spectra showed that chitosan and gelatin could form a complex by the reaction of -NH2 in chitosan and-COOH in gelatin.