In　this　study,　a　novel　fluorescent　probe　of　acridine　derivative　N-((N-(2-dimethylamino)ethyl)acridine-4-carboxamide)-α-alanine　(N-(ACR-4-CA)-α-ALA)　was　synthesized.　The　structure　of　the　new　compound　was　characterized　by　1H　NMR,　MS,　elemental　analysis,　fluorescent　and　ultraviolet　spectra.　It　was　found　that　DNA　had　the　ability　to　quench　the　fluorescence　of　N-(ACR-4-CA)-α-ALA,　and　the　quenched　intensity　of　fluorescence　was　proportional　to　the　concentration　of　DNA.　A　method　for　DNA　determination　based　on　the　quenching　fluorescence　(λex　=　260　nm,　λem　=　451　nm)　of　N-(ACR-4-CA)-α-ALA　was　established.　Under　optimal　conditions,　the　linear　range　is　0.05-2.0　μg　mL-1　for　both　fish　semen　(fsDNA)　and　calf　thymus　DNA　(ctDNA).　The　corresponding　determination　limits　are　9.1　ng　mL-1　for　fsDNA　and　8.7　ng　mL-1　for　ctDNA,　respectively.　The　results　suggested　that　the　interaction　mode　between　N-(ACR-4-CA)-α-ALA　and　DNA　was　intercalative　binding.　The　intrinsic　binding　constant　was　determined　and　the　result　showed　a　large　binding　constant　of　N-(ACR-4-CA)-α-ALA　with　DNA.　©　2008　Elsevier　B.V.　All　rights　reserved.