With　the　application　of　DC　microgrids　more　and　more　widely,　the　coordinated　control　study　among　multiple　microgrids　is　significant.　This　paper　proposes　a　microgrid　cluster　topology　and　based　on　it　a　coordinated　control　method　is　studied,　which　could　realize　the　optimized　management　of　power　flow　among　multi-microgrids　through　the　piecewise　adjustment　of　common　bus　voltage.　This　strategy　analyzes　the　power　distribution　inside　DC　microgrids　and　divides　the　operation　states　into　three　different　modes,　where　different　mode　has　diverse　external　characteristics.　According　to　the　external　characteristics,　the　piecewise-droop　control　strategy　of　the　grid-connected　converters　is　designed,　which　can　realize　the　coordinated　control　of　energy　and　improve　the　utilization　of　renewable　energy.　The　correctness　and　effectiveness　of　the　proposed　method　are　verified　by　simulation　results.　©　2021　IEEE.