The　applications　of　triboelectrification　have　attracted　much　attention　due　to　the　direct　regulation　of　charges　with　external　mechanical　stimuli.　Atomic　force　microscopy　(AFM)　is　an　effective　method　to　achieve　controllable　nanoscale　friction.　Herein,　we　demonstrated　a　phase　transformation　from　the　brownmillerite　SrCoO2.5　(BM-SCO)　to　perovskite　SrCoO3-delta　(PV-SCO)　as　modulated　by　nanoscale　friction　with　the　contact　mode　AFM.　Besides,　such　phase　transformation　can　be　reversible　by　applying　a　negative　voltage.　More　importantly,　when　defining　the　surface　potential　of　different　phases　as　binary　bits　of　＂1＂　and　＂0＂,　we　could　reach　high-density　data　storage　as　the　surface　charge　is　constantly　written　and　erased　in　nanoscale　regions.　This　work　opens　a　new　way　for　the　regulation　of　phase　transformation　by　triboelectrification,　and　realizes　the　surface　charge　patterning　based　on　different　phases　at　the　nanoscale　by　AFM　tip　friction,　which　is　of　great　significance　for　the　application　of　nano　devices　in　high-density　data　storage.