The relationship and genetic diversity among 84 Arachis gerplasm of 24 species belonging to 6 sections were systematically investigated based on SSR markers. 59 SSR primer pairs with polymorphic bands ranging from 1 to 6 were selected through 206 primer pairs screening. The genetic distance varied from 0.04 to 0.93 with average of 0.64 among Arachis species. Two accessions (G4 and G5) of A. appressipila belonging to section Procumbentes showed the least distance (0.04), while the largest genetic distances was detected between G14 (A. rigonii) belonging to section Procumbentes and G28 (A. glabrata) belonging to section Rhizomatosae. This clustering result was almost consistent with the taxonomic of Section in Arachis by Krapovickas and Gregory in 1994. The 7 genotypes of cultivated peanut were grouped into one cluster in section Arachis, and different botanical types were grouped into different sub-clusters. Section Procumbentes had the closest relationship with Section Arachis, while the relationship between sections Heteranthae and Erectoides were very closer. Some diploid species including A. villosa, A. duranensis and A. benensis had closer relationship with cultivated peanut based on the dendrogram, and they could be used as bridge genotypes to transfer elite genes from wild species to cultivated peanut.