Abstract: The simplified model of large flexible spacecraft——the hybrid system of rigid body with flexible panels which were partially bonded with active constrained layer damping treatments,was studied.By virtue of quasi-coordinates Lagrange's equations,the dynamics equations including all of the high order terms were derived.In the process of modeling,the motions of the rigid body and the active constrained layer damping plates were decribed by hybrid coordinates,the complex modulus of damping material was described by Golla-Hughes-Mctavish(GHM) model.Based on these dynamics equations,the active constrained layer damping vibration controller of the solar panels can be designed,and also,the attitude dynamics of large flexible spacecraft can be studied.