Abstract: In order to establish an efficient coupling method for analyzing the temporal status of the engineering slope from different viewpoints this paper educes the reliability level used in possibility design method by coupling FLAC3D with possibility design method(FOSM) and equilibrium method(simplified Bishop method),and judges the stability of slope by synthesis index composed of mechanical behavior,stability factor and the failure probabil-ity.The study results indicated that this method is feasible and credible.