Abstract: A supercavitating vehicle is a complex high-speed underwater body that is exposed to extreme operating conditions due to its speed. To successfully control the depth and attitude, it is necessary to study the motion characteristics of the vehicles on a vertical plane. This study investigates the motion model on the vertical plane and analyzes the dynamic characteristics of supercavitating vehicles. Then, a fixed-depth control method is developed. For validating the designed control-algorithm, related simulation and experiments have been carried out for the control system. Analytical results show that the proposed control system accomplishes precise depth control of the supercavitating vehicles, providing a necessary theoretical basis for further study of the dynamic control problem for underwater supercavitating vehicles.