In　regard　to　geotechnical　problems,　the　numerical　manifold　method　(NMM)　has　many　particular　advantages　over　the　finite　element　method　(FEM)　in　many　aspects.　In　the　present　paper,　a　numerical　model　called　SRNMM-GPS　method　is　further　proposed　for　slope　stability　analysis.　In　the　proposed　numerical　model,　a　strength-reduction　-based　NMM　(SRNMM)　is　firstly　adopted　to　predict　slope＇s　safety　factor　and　generalized　plastic　strain　(GPS)　field　that　corresponds　to　the　slope＇s　limit　equilibrium　state.　Then,　a　group　of　useful　points　locating　within　the　plastic　zone　of　the　slope　are　determined.　With　these　points,　an　improved　version　of　least　square　method　is　adopted　to　obtain　a　rational　critical　slip　surface　(CSS),　which　passes　through　the　point　with　the　maximum　value　of　GPS　near　the　toe　of　the　slope.　The　proposed　SRNMM-GPS　method　is　verified　with　some　typical　examples.　The　proposed　method　deserves　further　investigation.