Part of wild flax species and cultivated species were used as materials for optimizing SRAP-PCR reaction system, and concentration gradient test was made for all factors in order to select and establish the optimal program and system fitting for amplifying high diversity, good reproducible and clear bands. This program and system could well meet the requirement of flax SRAP and prove that SRAP marker was feasible for researching genetic polymorphism of flax. Part of wild flax species and cultivated species were used as materials for optimizing SRAP-PCR reaction system, and concentration gradient test was made for all factors in order to select and establish the optimal program and system fitting for amplifying high diversity, good reproducible and clear This program and system could well meet the requirement of flax SRAP and prove that SRAP marker was feasible for researching genetic polymorphism of flax.