[Objective] The study aimed to introduce a rapid and effective method that is suitable for extracting genomic DNA from animal and plant. [Method] The genomic DNAs were extracted from tender leaves of 24 peanut cultivars and from the liver,lung and kidney of white mouse through the specifically modified CTAB method. The DNAs were run on agarose gel,next detected by DNA/Protein analyzer. Finally PCR amplification was conducted to detect the quality of DNAs extracted using the modified CTAB method. [Result] The clear and orderly bands were observed in gel detection,and the values of OD260/OD280 for DNAs extracted via modified CTAB method were between 1.77-1.83. The DNAs performed well in PCR amplification. [Conclusion] The DNAs extracted by modified CTAB method could satisfy the requirement of PCR amplification.