The diving plane motion of autonomous underwater vehicles (AUVs) is a complex multivariable nonlinear system with pitch-heave coupling. Tornambe's controllers (TCs) can online estimate the dynamic uncertainty regardless of the type of disturbance. The TCs for depth and pitch angle are adopted to achieve multivariable decoupling control by introducing virtual control inputs. The methodology can obtain fast and non-overshoot control of depth and pitch angle in the diving and floating process. Simulation results demonstrated the effectiveness of the proposed control scheme.