In order to realize the effective protection of avalanche diode of military laser rangefinder, the basic properties of VO₂ film under 1064nm laser irradiation are tested, and the relationship between transmittance and film thickness before and after phase transition is obtained. The influence of different thickness of VO₂ film on the minimum saturation incident laser threshold of C30950E avalanche diode is also obtained, and the fitting formula is given as well. The experimental results show that with the increase of film thickness, the minimum saturation incident laser threshold of avalanche diode increases gradually. The minimum saturation incident laser threshold of avalanche diode can be increased from 5×10^-6W to 1.2×10^-5W when the film thickness is 200 nm. At present, there are few researches on laser protection of avalanche diode of military laser rangefinder in China, and most of them are limited to the theoretical level and lack experimental data support. Therefore, the feasibility of using VO₂ thin film for avalanche diode protection of military laser rangefinder can be further verified by the data and fitting formula provided in this paper. The data reference is also provided for further research on avalanche diode protection of various laser ranging equipment.