Abstract: Objective To find an ideal method of DNA isolation from blood, especially from clotted blood, to minimize the volume of blood collected for laboratory and clinical tests. Methods DNAs were isolated from antiagglutinating and agglutinating blood samples that were withdrawn from auricular veins of 60 healthy subjects. The DNAs of these samples were obtained by a nonenzymatic, nontoxic procedure optimized by us and determinated by agarose gel electrophoesis and PCR. Results The yields of DNA isolated from clotted blood and antiagglutinating blood were 40.2 ± 8.86 mg /L and 39.1 ± 10.2 mg /L ，and purities were 1.87 ± 0.11 and 1.92± 0.12. The DNAs that we isolated from all samples had high molecular weight and by PCR the dimorphism of Alu alleles of the 8th intron of t-PA was easy to be obtained, so they were complete and reliable. Conclusions The results showed this method is rapid, easy, efficient and nontoxic for isolation of DNA from clotted and fresh blood and it is suit for clinical testing and molecular biology study.