Chitosan/ nano-sized TiO2 film can be used as a preservative film, but its water resistance needs to be improved. Glutaraldehyde was used as crosslinking agent and crosslinks with chitosan to improve the water resistance of chitosan/ nano-sized TiO2 film. Quadratic regression mathematical model of mechanical properties, water absorption rate with the amount of glutaraldehyde, crosslinking time, and adding amount of TiO2 sol was established using quadratic general rotary design experimental method. The optimum process conditions for preparation of chitosan/ TiO2 nanometer films was obtained, which is cross-linked by glutaraldehyde as crosslinking agent 0. 10 g/ (100 mL) acetic acid solution, cross-linking time 4. 37 h, adding amount of TiO2 sol 0. 08 ml/ (100 mL) acetic acid solution. The tensile strength obtained under this condition is 5. 69 MPa, water absorption rate is 133. 66%. Its water absorption rate is decreased by 72. 8% compared with chitosan/ nano-sized TiO2 film.