An efficient DNA extraction method was developed for peanut seed, where only 3-5 mg cotyledonary tissue was enough for more than 50 PCR reactions with a reaction volume of 15 μl. Both low copy number and high copy number DNA sequences were successfully amplified. Processing one seed sample only took about half an hour. Sampling had no significant effects on germination and development. The DNA extraction method makes it possible to identify transformants and conduct molecular marker studies prior to sowing, and thus may greatly hasten research progress.