In order to study the feasibility of underwater launch of UAV and its dynamics performance of ejection process,the influence law and sensitivity analysis of the main parameters of the system were carried out.By studying the coupling characteristics of the mechanical structure and transmission system,a dynamics joint simulation model of the underwater launch test system based on AMESim and ADAMS was established,and the simulation was carried out for three types of UAVs in the range of launch angle 10° to 90° to obtain the variation law of the launch speed with launch angle and gas cylinder pressure;using the local sensitivity analysis method,the four key parameters of cylinder pressure,cylinder volume,effective area and stroke were analyzed to influence the launch speed and acceleration time.The results show that under the same pressure,as the launch angle increases and the mass of the drone model decreases,the speed of its detachment from the launch platform gradually increases;the parameter that affects the launch speed sensitivity most is the cylinder pressure,and as the pressure increases,the amplitude of the speed increase gradually decreases;the parameters that affect the acceleration process time sensitivity most are the cylinder pressure and the effective area of the cylinder.