The enhancement of the Resonance Light Scattering (RLS) due to Victory blue-B on the molecular surface of DNA in alkalescence solution was studied. A method of resonance light scattering was developed to determine DNA. Deoxyribonucleic acid(DNA) was studied in the range of pH 9.0-10.5. The effects of interference substances and optimization of procedure were investigated and a new method was established for the determination of DNA at nanogram level based on RLS measurement. The linear range of the DNA is 0-3.0 mg.L-1 with a correlation coefficient of 0.997 8. The detection limit is 21.5 mug(.)L(-1). The method has been applied to the determination of DNA in mixed samples with satisfactory result.