For the strong coupling characteristics of pitch, yaw and roll channels in the attitude control system of a hypersonic vehicle, a coupling controller is designed based on the state feedback and the dominant pole assignment of the Dutch roll mode to realize the system decoupling but improve the maneuverability of the vehicle. The new diagonal dominance matrix and row radius coefficient are introduced to analyze the coupling characteristics and degree of the system. Then based on this, the coupling PID controller is briefly designed as a comparison with the coupling controller. In addition, the lateral stability of the vehicle is analyzed, and the sensitivity of the coupling control system to runaway is measured based on the Weissman criterion. Finally, the simulation results show that the designed coupling controller has more precise control effect and less rudder deflection than the decoupling controller, which has a certain practical engineering significance.