The interaction of Water-soluble metalloporphyrin Cu(NACN) [Cu(4-N-acetonitrilepyridyl)porphine]With DNA was studied by UV-visible electronic and resonance Raman spectra.The analysis demonstrates: Cu(NACN) interacts with DNA by grove-binding; the pyridyl groups of Cu(NACN) were rotated a small angle toward perpendicular direction of porphyrin core Plane upon interaction with DNA;Cu(NACN) forms exciplex with DNA upon excited at 445nm Pulse; the interaction of excited Cu(NACN)with DNA is much more stronger than that of ground Porphyrin-DNA complex.