In　South　China,　the　geosynthetic　reinforced　retaining　wall　using　high　liquid　limit　soil　as　backfill　is　applied　widely.　Because　of　climate　change,　the　suction　between　unsaturated　high　liquid　limit　clay　and　geotextile　is　altering;　thus　influencing　the　interface　shear　characteristic.　So　the　interface　shear　characteristic　between　unsaturated　high　clay　and　geotextile　considering　suction　change　should　be　studied　deeply.　In　this　paper,　a　series　of　direct　shear　tests　are　performed　using　ZFY-1A　direct　shear　apparatus　to　investigate　the　shearing　resistance　properties　of　high　plasticity　clay-geotextile　interface　under　suction　cycle.　Results　of　experiment　indicate　that　the　peak　shear　strength　of　the　soil-geotextile　interface　increases　with　the　net　normal　stress.　Interface　strength　increases　at　first　and　then　reduces　with　the　increase　of　cycling　times,　interface　strength　is　lowest　through　3　times　of　the　dry-wet　circulation.　And　interface　strength　is　reduced　in　general.　δb,　δ＇　c＇a,　f＇　and　K　increase　and　then　decrease　with　the　increase　of　cycling　times.　ΔWmax　increases　with　the　cycling　times　and　net　normal　stress.　(h/H)max　decreases　with　net　normal　stress,　and　increases　then　decreases　with　the　increase　of　cycling　times.　Finally,　the　interface　strength　formula　under　different　suction　conditions　is　obtained　through　the　logarithmic　fitting.