A　performance　test　was　conducted　on　dredged　sand　found　in　the　lower　reaches　of　the　Yangtze　River　and　manufactured　sand　concrete　(Dredged　sand　and　Manufactured　sand　Concrete-DMC),　aiming　to　realize　the　comprehensive　utilization　of　dredged　sand　and　expand　the　source　of　fine　aggregates.　We　used　five　DMC　samples　with　different　dredged-sand　content　and　proportions　and　studied　their　micro-structures　and　properties.　The　correlation　between　the　microstructure　char-acteristics　and　mechanical　properties　of　the　samples　was　evaluated.　The　results　show　that　with　an　increase　in　the　ultra-fine　dredged-sand　content,　the　compressive　strength　of　the　specimens　first　increases　and　then　decreases.　When　the　content　of　dredged　sand　is　25%,　DMC　exhibits　better　mechanical　properties　and　work　performance.　Adding　the　correct　amount　of　dredged　sand　can　increase　the　density　of　DMC　and　reduce　porosity,　improve　the　uniformity　of　pore　distribution,　reduce　harmful　pores,　improve　the　structure　of　the　transition　zone　of　the　DMC　interface,　and　optimise　the　phase　composition,　but　it　causes　the　pore　morphology　to　decrease　to　a　certain　extent.　Compared　with　the　blank　control　group,　excessive　mixing　of　dredged　sand　can　still　improve　the　mechanical　properties　of　DMC.　The　Correlation　studies　have　proved　that　microstructure　char-acteristic　parameters　of　the　DMC　such　as　porosity　can　be　improved　by　changing　the　content　of　dredged　sand　and　realizing　the　improvement　of　DMC　compressive　strength.