Abstract: The total DNA of endangered plant Cycas simplicipinna (T.Smitinand) K.Hill was extracted by means of improved CTAB isolation method.SSR primers were screened using 91 individuals of five populations of C.simplicipinna from 65 nuclear SSR primers which had been developed from other cycas plants.And the genetic diversity indexs of screened SSR primers were analysed.As a result,we totally got 20 SSR primers which had high polymorphism in C.simplicipinna.With respect to the 20 primers,the average of numbers of alleles was 9.75,the average of effective numbers of alleles was 4.769,the average of Shannons information index was 1.473,the average of observed heterozygosity was 0.380,and the expected heterozygosity was 0.636,there was only the fixation index of primer 4 smaller than 0.Most of these primers deviated from Hardy-Weinberg equilibrium and reached the most significant difference level.These results will provide references for genetic diversity and genetic structure research of C.simplicipinna.