In　recent　years,　there　has　been　significant　progress　in　the　development　of　flexible　sensors　for　human-machine　interfaces.　However,　the　triboelectric　principle,　especially　which　based　on　sliding　mode,　is　relative　rarely　applied　to　flexible　strain　sensors.　Therefore,　a　novel　triboelectric　flexible　stretchable　sensor　has　been　designed　with　a　simple　structure,　convenient　fabrication　process,　and　effective　response　to　various　strain　signals　(Within　the　range　of　0%-200%,　the　average　sensitivity　is　49.07　mV　per　1%　strain).　This　sensor　operates　in　a　new　triboelectric　working　mode:　variable　charge　density　mode　(VCD　mode).　Furthermore,　the　sensor　can　also　be　utilized　for　tactile　sensing　in　vertical　contact-separation　mode　without　any　structural　modifications.　Based　on　this　strain-tactile　dual-mode　flexible　triboelectric　sensor　(STDFTS),　its　applications　for　human-machine　interface　have　been　explored:　gesture　recognition　(recognition　accuracy　of　five　gestures　reaches　99.4%)　based　on　tactile　sensing　and　mouse　replacement　based　on　dual　working　modes.　The　STDFTS　proposed　in　this　article　provides　a　new　alternative　solution　for　human-machine　interfaces,　greatly　expanding　the　application　scenarios　of　triboelectricity.　The　sensor＇s　innovative　design　and　dual-mode　functionality　open　up　new　avenues　for　research　and　development　in　the　field　of　triboelectric　nanogenerator,　flexible　sensors　and　human-machine　interaction.