Abstract: This research aimed to isolate high quality genomic DNA from the mature leaves of Paphiopedilum armeniacum using CTAB method，improved CTAB method，high salt low pH method and SDS method. The quality of genomic DNA including integrity and purity was examined through OD value and agarose gel electrophoresis. The results showed that the genomic DNA obtained from the mature leaves of P. armeniacum with CTAB method and high salt and low pH method had poor purity，poor integrity and low yields，and the DNAs were degraded seriously and polluted by proteins. The genomic DNA extracted by the SDS method was intact without degradation，but was polluted by proteins and the DNA purity was low. Fortunately，the genomic DNA obtained by improved CTAB method was intact without degradation，had higher purity and higher yield. The ratio of A260/A280 is 1.7–1.9. It was proved that proteins，polyphenols and polysaccharides rich in the leaves cells of P. armeniacum，could be removed effectively，which had high purity and quality and could be used in molecular biological research，like PCR directly.

Key words: Paphiopedilum armeniacum, DNA extraction, CTAB method, SDS method, comparison