In order to systematically analyze the genetic diversity of naked oat germplasm resources and screen excellent breeding materials, 26 agronomic and phenological traits related to the growth period of 481 naked oat germplasm were compared and analyzed for genetic variation, and the genetic differentiation patterns of agronomic traits were clarified through variation degree analysis and genetic diversity parameter evaluation, while a comprehensive evaluation system for naked oat germplasm resources was established by adopting the combined method of principal component analysis and cluster analysis.The results showed that the tested naked oat germplasm accessions exhibited extensive genetic variation in the investigated agronomic traits, with an overall high level of genetic diversity. Among the qualitative traits, spike type had the highest genetic diversity (0.9167); while among the quantitative traits, puncture strength ranked first in terms of genetic diversity index (2.0663), followed by plant height (2.0644)，and the effective tiller number had the largest coefficient of variation (65.26%). A total of 5 principal components were identified via principal component analysis, with a cumulative contribution rate of 74.928%. These components incorporated 17 agronomic traits, namely plant height, spike length, number of effective tillers, number of spikelets per main panicle, number of grains per main spike, number of grains per plant, grain weight per plant, number of spikes per plant, number of leaves on main stem, number of spike whorls, number of spikelets per main spike, compressive strength, bending performance, puncture strength, flag leaf length, flag leaf width and stem thickness. Based on cluster analysis, the 481 naked oat (Avena nuda L.) accessions were classified into 4 major clusters, and one specific outlier germplasm with a significantly distant genetic relationship was simultaneously identified. Group Ⅱ can serve as elite parental materials for high-yield breeding; Group Ⅲ as fundamental germplasm resources for broad-adaptability breeding; Group Ⅴas parental lines with strong tillering ability. Sixty-seven elite germplasm accessions with outstanding comprehensive traits were screened out, providing precise parental support for the directional breeding of naked oat.