This kit is suitable for isolation of purified high-quality genomic DNA from blood samples. The kit uses a magnetic bead and buffer system with a unique isolation function.The surface of the magnetic bead is modified with special chemical groups, which have extremely strong enrichment ability for genomic DNA under certain conditions and can reversibly release genomic DNA when the conditions are changed, to rapidly separate and purify genomic DNA, and to remove impurities like proteins as far as possible. The genomic DNA extracted by this kit can be widely used for various routine operations,such as enzyme digestion, fluorescent quantitative PCR, library construction, Southern blotting, chip detection and other experiments.