Abstract: In this paper,the non linear stability analysis of laminated composite plate under compression loading is demonstrated by use of Hahn-Tsai nonlinear constitutive relationship. The initial stresses of the plate is the prebuckling state ire obtained by completed plate theory. Numerical results have proved that inplane boundary constraints of the edges could have significant effect on the load capability of the plate,which is quite different from the conclusion given by membrane theory in prebuckling state.