Abstract: Based on the kinematic model of hypersonic reentry vehicle, coupling effects between three channels were comprehensively analyzed, including kinematics coupling, inertial coupling, aerodynamic coupling and control coupling. To solve the attitude tracking problem of the strong coupling system, ADRC(active disturbance rejection control)-based trajectory linearization controllers were designed based on time-scale separation and singular perturbation theory for attitude and angular rate loops respectively. During design process, decoupling mechanism of ADRC-based trajectory linearization control were analyzed fully from perspective of feedforward, feedback, disturbance estimation and compensation. The simulation results show the correctness of the decoupling mechanism analysis and excellent decoupling effects of ADRC-based trajectory linearization control possesses, being suited to design controller for strong coupling systems.