Abstract: Abstract: Using one of the excellent germplasm resources of bramble Rubus coreanus as material, three different DNA-extracting methods (SDS method, CTAB method and modified CTAB method) were employed to be compared in order to isolate high-quality genomic DNA from young leaves. The results showed that the SDS method, the CTAB method and the modified CTAB method can extract DNA. But the modified CTAB method was better than the other two methods, because it could obtain high quality DNA with less impurity. By orthogonal design, a satisfactory ISSR reaction system was established, i.e. a total volume of 25 μl system, it contained 1×PCR Buffer, 2 mmol/L Mg2+, 1.5 U Taq DNA polymerase, 0.2 μmol/L primer, 0.4 mmol/L dNTP and 20 ng DNA template. We tested this reaction system and it worked well with primer UBC835 using in ten bramble cultivars and UBC873 using in eight bramble wild materials.