An underwater gliding snake-like robot (UGSR) combines the advantages of an underwater glider (UG) and an underwater snake-like robot (USR) to achieve both long endurance and high maneuverability. This paper investigates the hybrid gliding motion of the UGSR, which is driven by net buoyancy and rotate joints. By decomposing the three-dimensional (3D) hybrid gliding into the buoyancy-driven gliding in the vertical plane and the serpentine swimming in the horizontal plane, a dynamic model is established. With consideration of system disturbances caused by unmodeled dynamics and noise, a nonlinear controller consisting of backstepping method and active disturbance rejection control (ADRC) is designed to realize the decoupling control of joint angles, velocities, pitch angle and head angle. Simulations results verify the tracking of the desired gliding states. © 2021, ICROS, KIEE and Springer.