A　fluorescence-enhanced　system　was　developed　for　the　determination　of　nucleic　acids　by　using　morin-aluminum(III)　complex　as　a　new　fluorescent　probe.　In　aqueous　solution,　morin-aluminum(III)　complex　showed　maximum　excitation　and　emission　wavelengths　at　420.0　nm　and　532.8　nm,　respectively,　and　its　fluorescence　could　be　greatly　enhanced　in　the　presence　of　nucleic　acids.　Under　optimal　conditions,　the　calibration　graph　was　linear　over　the　range　0.25-1.50　mug(.)mL(-1)　for　fish　sperm　DNA,　0.10-1.60　mug(.)mL(-1)　for　salmon　sperm　DNA,　0.25-2.00　mug(.)mL(-1)　for　calf　thymus　DNA　and　0.25-2.00　mug(.)mL(-1)　for　yeast　RNA.　The　corresponding　detection　limits　are　3　ng(.)mL(-1),　2　ng(.)mL(-1),　2　ng(.)mL(-1)　and　3　ng(.)mL(-1),　respectively.　Applied　for　the　determination　of　nucleic　acids　in　synthetic　samples,　the　relative　standard　deviation　for　five　replicates　is　less　than　3.6%,　and　the　recovery　ranges　from　93.3%　to　107.9%.　Additionally,　the　interaction　mechanism　of　morin-aluminum(III)　with　nucleic　acids　is　also　discussed.