This kit uses a centrifugal adsorption column that can specifically bind nucleic acids and a unique buffer system. After the sample is cracked, the DNA is bound to the silicone membrane under high salt conditions, and the DNA is eluted from the silicone membrane at low salt and high pH value. This kit is used to extract genomic DNA from small doses of blood, dry blood points, serum, plasma, trace tissue, mouthwash, hair, micro-cut tissue and other trace samples. The genomic DNA obtained can be directly used as PCR template, enzyme digestion, hybridization and other molecular biology experiments.