We　report　high　energy　low-repetition-rate　graphene　mode-locked　Er-doped　fiber　laser　with　a　long　ring　cavity.　The　stable　227　kHz　nanosecond　pulse　is　generated　at　diode　core-pumped　power　of　44　mW.　Increasing　the　pump　power　to　110　mW,　we　achieved　the　maximum　output　power　of　15　mW,　corresponding　to　single　pulse　energy　of　66　nJ.　The　pulse　width　was　measured　to　be　16　ns.　The　spectral　central　wavelength　was　1559.6　nm　and　3dB　bandwidth　of　the　emission　spectrum　was　0.76　nm.　The　time-bandwidth　product　(TBP)　of　the　pulse　was　similar　to　1499,　indicating　that　pulses　were　highly　chirped.　To　the　best　of　our　knowledge,　this　is　the　first　report　for　graphene　mode-locked　Er-doped　fiber　laser　in　such　low　repetition　rate　and　high　pulse　energy.