Abstract: abstract: The total DNAs of Dioscorea opposite Thunb were extract by the improved CTAB method, and set the gradient by single factor experiment with template DNA concentration, Primer concentration, dNTP concentration, Taq concentration and Mg2+ concentration, Study on the effect of single-factor change on D. opposite RAPD-PCR amplification. In conclusion, the D. opposite reaction system was optimized as below: 50ng template DNA, 0.3U Taq DNA polymerse, 3.0mmol/L Mg2+,0.2μmol/L primer and 0.2mmol/L dNTPs with total 20μL reaction solution.