A method for genomic DNA extraction of Juglans regia from its young leaves was modified by CTAB,considered that plants are rich of secondary substances such as polyphenols and polysaccharides.The protein,polysaccharide and RNA were eliminated completely after genomic DNA was electrophoresed in 0.8% agarose gel.This genomic DNA may be used for many functional genomic based experiments such as molecular marker and the research of molebiology.