The invention discloses a novel multi-vehicle series water entry light-gas gun launching experimental device. The device comprises a tripod; a motor and a light-gas gun launching device are fixed ontothe upper surface of a tripod pan-tilt holder; the light-gas gun launching device is provided with a plurality of light-gas gun tubes and a rotating shaft; the output shaft of the motor is connectedwith the rotating shaft; one end of each light-gas gun tube, which is adjacent to the motor, is fixedly provided with a compressed gas cylinder; a vehicle is arranged in one end of each light-gas guntube adjacent to the motor; one end of each light-gas gun tube, which is far away from the motor, is provided with a front-end support; a level is fixed on the tripod; and the light-gas gun tubes areprovided with speed measuring devices respectively. According to the novel multi-vehicle series water entry light-gas gun launching experimental device of the invention, the light-gas guns are adoptedto launch vehicles; the light-gas guns are arranged on the tripod; the inclination angle of the light-gas guns is so accurate that the inclination angle can reach a 0.1 degree-level; by means of a servo motor, the plurality of vehicles can densely enter water at the same position, and can enter water synchronously in a parallel manner at a certain initial speed, and namely, the series water entryand parallel water entry of the vehicles can be realized.