Abstract: One hundred pairs of SRAP primers were screened by using Oriental lily varieties including‘Sorbonne’,‘Constantsa’ and their hybrid offspring as materials. As results,59 pairs which had rich products and high polymorphism were selected,and the PCR reaction system were also optimized. First of all, an orthogonal design with four factors and four levels was adopted to optimize the concentration of Mg²⁺, dNTPs, Taq DNA polymerase and primers. Then the concentration of Mg²⁺, primers and annealing temperature was analyzed with a single-factor design. It was revealed that the optimal reaction system was: 1×Buffer,Mg²⁺ 2.7 mmol/L,dNTPs 0.25 mmol/L, primers 0.8 μmol/L, Taq DNA polymerase 1.5 μmol/min, and DNA 60-100 ng. The optimal annealing temperature of SRAP two-step reaction was 35 ℃(first step)and 59.3 ℃(second step).