Sorghum germplasm is vital for genetic improvement and cultivar development, and assessing its genetic diversity is essential to broaden the genetic base. In this study, we evaluated the genetic diversity of 12 agronomic traits in an Australian sorghum nested association mapping (NAM) population (288 accessions) at two locations, within one year using multiple analyses. Coefficients of variation for all traits ranged widely from 9.51 to 56.94%, with panicle shape showing high genetic variation. The Shannon-Wiener diversity index ranged from 1.1091 to 2.0725, and leaf length exhibited relatively high diversity. Correlation analysis revealed varying degrees of correlation among the 12 traits; thousand?grain weight, panicle length, and leaf traits were correlated with multiple traits and can serve as indicators for synergistic improvement. Cluster analysis classified the population into three groups with distinct trait profiles. Group A (tall plants, heavy panicle grain weight, thick stems) was suitable for dual?purpose (grain and forage) breeding; Group B (short stature, short panicles) can be used as core germplasm for dwarf sorghum breeding; Group C (long panicles and long main peduncles) was suitable for craft use. Principal component analysis extracted four principal components accounting for 63.395% of total variance, primarily capturing variation in plant architecture, panicle traits, yield, and quality. Comprehensive evaluation identified accessions T444, T566, and T472 as elite germplasm with superior overall traits for further research. This population exhibits a broad genetic background and distinct phenotypic differentiation, providing elite parents and a novel genetic basis for sorghum breeding in China.