Abstract: For further enriching genetic diversity information of phenotypic traits on Chinese chestnut germplasm resources，9 phenotypic traits related to biennial bearing branch of 164 Chinese chestnut germplasms from 10 provinces（as 10 populations）were designed with hierarchical classification and then were done with analysis of variance and systematic cluster analysis. The results showed that differences among and within populations of 9 phenotypic traits value were highly significant，indicating a wide range of variation existed in these two levels. The average variation coefficient of the 9 phenotypic traits was 19.4%–64.0%，especially，variation coefficient concerning 3 of the 9 traits including the average male flower shoot number/biennial bearing branch，the delicate shoot number/biennial bearing branch and the average bur number/branch，reached > 40%，which suggested that the germplams had a great potential of genetic breeding in the 3 phenotypic traits. The average of phenotypic differentiation coefficient among populations and within populations were 65.9% and 34.1%，respectively，illustrating that the variation among populations was the leading source of trait variation. The systematic cluster analysis showed that 10 populations can be divided into 4 groups based on the variation of phenotypic traits，which indicated that the phenotypic traits of Chinese chestnut populations were basically clustered according to geographical distance.

Key words: chestnut, phenotypic traits, within populations, among populations, diversity