Abstract: In order to explore phenotypic variation and diversity of Tilia mandshurica natural populations,and to provide reference for the selection,protection,and utilization of T.mandshurica germplasm resources.Leaves and fruits from eight T.mandshurica natural populations were measured for the determination of 11 phenotypic traits,and the phenotypic traits from different populations were compared by variance analysis,coefficient of variation and Shannon-Wiener index,and eight populations were conducted by principal component analysis and cluster analysis.Variance analysis showed extremely significant differences in leaf and fruit traits among different populations and within populations,and the percentage of variance component among populations for each trait was higher than that of within populations,and phenotypic differentiation coefficients ranged from 0.83-0.95,and the main source of phenotypic differences was from different populations.The coefficient of variation of different traits ranged from 20.0%-39.9%,indicating a large degree of variation.The ShannonWiener index of different traits from different populations ranged from 1.262-1.443,indicating rich phenotypic diversity populations.The 11 phenotypic traits were divided into four principal components,with a cumulative variance contribution rate of 88.46%.According to the principal component comprehensive model,the comprehensive ranking of the eight populations from high to low was Hunchun,Longtan,Huinan,Jiaohe,Dongfeng,Dunhua,Huadian and Luobei.According to leaf and fruit traits,the eight populations were clustered into three groups,among which Dongfeng and Luobei had relatively larger leaf,while Dunhua,Hunchun,Huadian,and Jiaohe belonged to the groups with larger fruit petiole and bract.The left populations,Longtan and Huinan belonged to the larger fruit group.The phenotypic traits of T.mandshurica natural populations exhibited significant variation and rich diversity,and the main source of phenotypic differences was from inter-population variation,and large gains might be achieved through selection.