Because　of　the　safety　factor　based　on　current　analysis　methods　can　not　reflect　the　real　safety　of　a　slope,　this　paper　proposed　a　new　method-reliability　analysis　method,　and　made　a　calculation　program.　Through　cases　analysis,　it　has　been　shown　that　through　the　safety　factor　are　the　same,　but　the　reliability　are　different.　The　authors　suggested　that　safety　factor　methods　should　be　replaced　by　reliability　method.