Abstract: The factors influencing RAPD Analysis, including 10×PCR Buffer, the concentration of DNA template, Mg2+, dNTP, primers, Taq polymerase, Thermal cycles and annealing temperature in Ramie were studied. PCR system for RAPD in Ramie has been found: in 25μl reaction solution, contained 0.4μM random primers, 60~100ng DNA template, 1.8mM Mg2+, 0.2 mM dNTP, 1U Taq polymerase. The suitable procedure is one cycle 94℃ for 4min; denaturing at 94℃ for 45s; primer annealing at 38℃ for 45s, extension at 72℃ for 2min, 36 cycles; extension at 72℃ for 5min at last and then remain at 4℃.