Abstract: In view of the characteristics of strong coupling and week damping, this paper studied the high efficiency lateral-directional modal control strategy of symmetrical aircrafts with coupling dynamics. The linear dynamic model in the stable axis system was derived and simplified expressions of the lateral-directional modal characteristics were obtained. The control strategies of improving the effective modal characteristics under the influence of coupling dynamics were proposed, and the control effectiveness expression of each strategy was derived. The criteria of high efficiency strategy selection were obtained through comparative analysis. Finally, the theoretical results were verified by root locus analysis, effectiveness evaluation of modal improvement strategy and 6-DOF simulation. The results show that the criteria proposed can accurately represent the efficiency relationship of different control strategies and can be used to guide the lateral-directional modal control scheme design of symmetrical aircrafts.