Abstract: Taking the seedling of Agropyron mongolicum Keng as tested material,and establish the optimal SRAP system of Agropyron mongolicum Keng by single factor tests of Mg2＋、dNTP、Taq、primer、DNA and orthogonal design approaches of 2×Taq PCR Master Mix、primer、DNA.The results indicated that：10uL reaction system is the most suitable system which containing 2uL 2×Taq PCR Master Mix,0.4umol/Lprimer,60ng template DNA.Using Agropyron mongolicum Keng to test this optimized SRAP system,and the electrophoresis results showed that the amplification bands were clear,highly polymorphic and Simple.This work is a foundation for applying SRAP marker to Agropyron mongolicum Keng molecular biology studies.