In order to reduce the production process of collagen casing film, and to improve the quality of packaging materials in food industry, the effect of glutaraldehyde addition sequence on the quality of collagen casing film was investigated. The tensile strength, elongation at break, thermal shrinkage, swelling rate, color and denaturation temperature were studied through three addition treatments, i.e., during the process of collagen paste making, after paste making, and after film forming, respectively. Results showed that glutaraldehyde could improve the mechanical properties and surface hydrophobicity, and decrease the swelling rate and thermal shrinkage rate of collagen casing films under any treatments. The results of FTIR and DSC showed that the films crosslinked with glutaraldehyde after film formation had the highest crosslinking efficiency and thermal stability, and the most significant improvement in film properties. Furthermore, with the increase of glutaraldehyde content, the color of casing film gradually changed yellow. However, when the content of glutaraldehyde was over 100 mg/L, there was no further significant improvements on the quality of casing films by the crosslinking of glutaraldehyde.