In order to study the characteristics of unsteady flow field of submarine-launched vehicles during salvo，based on the dynamic grid technology，the VOF multiphase flow model and the User Defined Function (UDF)，this paper conducted numerical simulation study on the salvo water-exit process of the double-vehicle， established a three-dimensional numerical model of the salvo water-exit of the double-vehicle. It studied the cloud image and forces characteristics in each stage of salvo water-exit process under typical operational conditions，and further analyzed the relations of launch speed and resistance on the vehicles. The following conclusions are obtained：1)When the launch distance is within a certain range，significant flow interference will occur between the vehicle bodies during the entire launch phase，which will have a great impact on the force characteristics of the vehicles. 2)The deflection torque experienced by the sailing body during the canister-exit phase is the largest，and it is easy to deflect，which affects the safety of underwater launch. 3)At different launch speeds，the maximum resistance experienced by the double-vehicle occurs during the canister-exit phase，and the launch speed is directly proportional to the resistance of the double-vehicle.
