Abstract: In order to optimize and establish the SRAP−PCR system for Castanopsis wenchangensis, the combination of single factor test and orthogonal test were used to analysis the effects of DNA, primers, dNTPs and Taq DNA polymerase on SRAP−PCR. The results showed that the genomic DNA concentration and dNTPs concentration were too low or too high to amplify the product, and the increase of primer concentration and Taq DNA polymerase could increase the amplification efficiency. Within the appropriate concentration range, the order of influence on the SRAP−PCR system for C. wenchangensis was: primer = dNTPs > Taq > DNA. The optimal reaction system was: when the total system was 20 μL, the DNA 20 ng, the primer 0.6 μmol/L, the dNTPs 0.15 mmol/L and Taq 4 U. It has been verified that the amplification products obtained by this system were clear and stable, 45 pairs of effective primer combination polymorphisms were obtained by screening, which can be applied to the research of SRAP molecular marker in C. wenchangensis resources.