Analyze the diversity of phenotypic traits of sesame germplasm in Jiangxi, and obtain a reliable primary core germplasm population of sesame, providing theoretical basis and reference for promoting further identification, preservation, development and efficient utilization of sesame germplasm. We use 736 sesame germplasm from various counties and cities in Jiangxi Province as experimental materials, diversity analysis was conducted on 25 phenotypic traits; Using QGAstation2.0 software, we can select to construct the best plan for primary core germplasm; Perform mean T-test and variance F-test on multiple parameters of the original germplasm and core germplasm, and compare the eigenvalues, contribution rates, and cumulative contribution rates of the two populations through principal component analysis; On this basis, genotype data of 64 Ji"an germplasms (including 736 sesame germplasms) were obtained using 12 pairs of polymorphic markers. Polymorphism analysis, evaluation, and genetic similarity analysis were performed on 16 germplasms (including 110 core germplasms) and 64 germplasms using SSR markers. The results showed that 736 local sesame germplasm in Jiangxi Province had rich genetic diversity. The genetic diversity index (GDI) of phenotypic traits ranged from 0.5129 to 2.0833, and the GDI of quantitative traits (1.7140~2.0833) was overall higher than that of qualitative traits (0.5129~1.2028);the primary core germplasm constructed by multiple clustering priority sampling method+15% sampling ratio+variable class average method+Euclidean distance can well represent the diversity of the original germplasm population; The cumulative contribution rates of the original germplasm population and core germplasm are 80.533% and 82.631%, respectively, indicating that the primary core germplasm can explain more than 80% of the genetic information of the original germplasm population; the six polymorphic parameter values of the original germplasm population and the core germplasm population are basically similar, and there is no significant difference in the mean t-test (except for the number of observed alleles). At the same time, the genetic similarity between the two populations is basically similar. The 16 core germplasm preliminarily represent the genetic diversity of 64 Ji"an sesame germplasm, further indicating that the 110 core germplasm can represent the genetic diversity of 736 Jiangxi sesame germplasm resources to the maximum extent for preservation and utilization.