Li-rich　cathode　materials　have　high　specific　capacities　which　exceed　250　mA　h/g,　but　the　arrangement　of　lithium　inside　them　will　cause　the　cations　of　transition　metals　to　be　mixed,　resulting　in　the　phase　change　and　capacity　loss　in　the　charge　and　discharge　cycle　process.　We　propose　surface　modification　by　Li2MnO3,　and　its　crystal　structure　is　in　consistence　with　the　structure　of　lithium-rich　manganese-based　oxides,　so　that　nickel　ions　can　be　orderly　arranged　between　the　transition　metal　layers　during　the　cycle.　We　prepare　Li1.2Mn0.54Ni0.13Co0.13O2　by　the　co-precipitation　method　and　coat　Li2MnO3　on　its　surface.　This　surface-modified　structure　will　reduce　the　phase　transition,　inhibit　the　irreversible　capacity　loss,　and　improve　the　structural　stability　and　cycle　stability.　The　specific　capacity　of　the　pristine　modified　by　5　wt　%　Li2MnO3　is　224　mA　h/g　at　300　mA/g,　and　the　capacity　retention　ratio　is　96.2%　after　100　cycles,　while　the　unmodified　pristine　under　the　same　conditions　is　only　197　mA　h/g　with　its　capacity　retention　ratio　being　75.9%.　In　addition,　the　modified　electrode　showed　better　initial　Coulombic　efficiency,　rate　capacity,　and　impedance　parameters.