Peanut (Arachis hypogaea L.) is an important oilseed and cash crop.The assessment of genetic diversity and population structure of peanut cultivars will contribute significantly to making use of these germplasms in genetic improvement and association mapping.In this study, 146 highly polymorphic simple sequence repeat (SSR) markers were used to assess the genetic diversity and population structure of 196 accessions of cultivated peanut from 13 provinces in China.These SSR markers amplified 440 polymorphic bands with an average of 2.99 bands and the average gene diversity index was 0.11, which indicated the genetic diversity of the 196 Chinese peanut cultivars was at a lower level.Eighty-six rare alleles with a frequency less than 1% were identified in these accessions, of which 13 unique rare alleles were found in genotype Nenghua 3 and 10 in genotype Jilinsilihong, both of the genotypes were collected from Jilin province of Northeast China.The greatest Fst or genetic distance was found between the accession groups from the regions of south and north of the Yangtze River.A neighbor-joining tree of the peanut populations from the thirteen provinces was constructed based on pairwise Neis genetic distances, showing that there could be significantly different between cultivars from south of the Yangtze River and from north of the the Yangtze River.A model-based population structure analysis divided these peanut cultivars into five subpopulations.P1a and P1b contained mostly the cultivars from south of the Yangtze River including Guangdong, Guangxi and Fujian provinces.The two cultivars from Jilin Province were clustered in P1 a.P2 population consisted of the cultivars from Hubei and parts of the cultivars from Shandong, Henan provinces.P3a and P3b had cultivars from north of the Yangtze River including Shandong, Hubei, Henan, Hebei, Jiangsu provinces and all 10 cultivars from Sichuan provinces.Cluster analysis, PCoA and PCA based on the marker genotypes revealed five distinct clusters for the entire population, which is related to their germplasm regions.The results presented in this study suggested that the genetic base of the peanut cultivars was narrow in China, and a wider range of accessions should be utilized for broadening genetic material and improving peanut cultivars.