A ring-like deposition technique is proposed to quantify trace amounts of DNA. Because of the capillary effect of solvent, which compensates for the evaporative loss at the contact line of a nanoliter sample droplet on a hydrophobic surface, materials of the droplet can be carried to the edge of the drop spot, and a ring-like deposit (RLD) can occur. Itwas found that a fluorescent deposit of α,β,γ,δ-tetrakis[4-(trimethylammonium)phenyl]porphine can occur on a dimethyldichlorosilane (DMCS)-modified glass slide, and the fluorescence emission of the deposit can be greatly enhanced by DNA. Linear responses were obtained between the maximum enhanced fluorescence intensity (△/max) and amount of calf thymus DNA (ctDNA) in the range 0.10-3.00 pmol, and fish sperm DNA (fsDNA) in the range 0.20-3.00 pmol. Limits of determination are 6.8 fmol ctDNA and 19 fmol fsDNA.