Missile launching process has an important effect on kinetic characteristic of light underwater vehicle compared to traditional submarine launching missile due to its small size，light weight and fast floating process. Aiming at light and fast floating underwater vehicle，a disturbance model of floating，launching and uncapping process is established. In addition，the typical floating and missile launching process is simulated and analyzed. The simulation results indicate that the disturbance of uncapping and launching process has a small effect on trajectory and attitude of vehicle，but has great influence on floating speed. The efficiency of control system degrades significantly after launch.
