DNzol is a reagent which can be entirely and directly used to extract genomic DNA. By using DNzol, DNA can be extracted fast from all kinds of samples, whatever mass or a little. The method is simple and efficient and the result is confident. Lyse cells and hydrolyze RNA can be done in the same step, then DNA can be quickly gained after deposited by ethanol, which only takes 10 to 30 minutes for whole process. The percentage of reclaiming DNA from sample can be up to 70-100%.The DNA can be used to Southern blotting, Dot blotting, molecular cloning, PCR and other molecular biology applications.