In order to study the underwater inflation process of a photoelectric buoy used for torpedo guidance, a numerical analysis model of gas cylinder inflation was established based on the gas control volume method. Relevant calculation parameters were set, and LS-DYNA was used to simulate the underwater inflation process of the airbag of the photoelectric buoy. Furthermore, the effects of parameters such as depth and inflation tube diameter on the deployment of the airbag were analyzed. The results indicate that the deployment time of airbags is significantly influenced by depth and the diameter of the inflation tube; the internal pressure of the airbag is less affected by depth, and is more affected by the diameter of the inflation tube, which can easily cause safety issues, the design size of the inflation tube diameter of the photoelectric buoy should be within 8 mm.