Abstract: To investigate the genetic diversity and authentication of this species in China and to probe into the phylogenetic taxonomy of the genus using molecular markers in the next step, two isolation methods of DNA (little extraction by SDS method and large amount of extraction by CTAB method), optimization of RAPD-PCR condition and primers screening were firstly studied. The results showed that both isolation methods could effectively obtain high quality DNA, and the DNA amount harvested from little extraction method could be used in RAPD-PCR action for one hundred times at least in spite of much less than the production from large extraction. Different labs may select any of them according to the demand of their experiments. The subsequent RAPD-PCR condition was explored, using the DNA harvested from both methods, and the most suitable mixture was as follows: total 25μl reaction volume containing template DNA 20ng, 10×Taq buffer 2.5μl, 2μl dNTPs (2.5mM), Mg2+2μl(25mM), Taq DNA polymerase 0.15μl (5U/μl), 0.5μl pimer (25μM) and ddH2O in the rest. Total nine stable and clear primers with high polymorphism were selected except for those with monomorphic and faint bands, using the DNA samples and the RAPD-PCR condition in our study.