Abstract: Twenty SSR primer pairs were used to amplify SSR fragments for 83 Fragaria materials which belonging to 14 species，natural pentaploid strawberry and the unknown species. The 20 SSR primers generated a total 363 alleles. The number of alleles per locus ranged from 8 to 34，and averaged 18.2. The value of allelic polymorphism information content（PIC） ranged from 0.6691 to 0.9431，and averaged 0.8598. The dendrogram result showed that the samples clustered clearly among the same species. Among the species，the three octoploid species F. chiloensis，F. virginiana and F. × ananassa were clustered together，which showed the closest relationship. The three octoploid species had the distant relationship from other species. F. corymbosa，F. pentaphylla，F. nipponica，F. yezoensis，F. tibetica，F. nilgerrensis and F. viridis were clustered together and have closest relationship. And F. vesca，F. mandschurica，F. oriebtalis，F. moschata and the natural pentaploid strawberry were clustered together and have closest relationship. The origin of natural pentaploid strawberry may come from the cross of F. oriebtalis，F. moschata and F. vesca，F. mandschurica.

Key words: Fragaria, germplasm, genetic relationship, SSR