The　determination　of　positions　of　critical　slip　surfaces　is　a　hot　spot　of　research　on　geotechnical　engineering.　In　two-dimensional　slope　stability　analysis　applied　with　finite　element-strength　reduction,　the　points　with　the　maximum　equivalent　plastic　strain　along　depth　are　mostly　on　the　critical　slip　surface　for　a　slope　at　limit　equilibrium　state.　One　set　of　wavy　signal　function　consisting　of　points　with　the　maximum　equivalent　strain　can　be　constructed　by　deploying　a　series　of　parallel　lines　approximately　perpendicular　to　the　slope　surface.　The　wavelet　analysis　smoothens　these　points　on　the　critical　slip　surface.　Through　the　classic　example　analysis　and　comparisons　with　Spencer＇s　method　and　other　previous　research,　the　results　show　that　the　method　in　this　paper　is　reasonable　and　effective,　and　can　be　used　to　locate　the　critical　slip　surface.　©　2017,　Science　Press.　All　right　reserved.