Abstract: Experiments were conducted on growth rhythm of Cleistocalyx operculatus seedlings in Guangzhou, Guangdong province in 2014. Theresults show that the growth of height and ground diameter of C. operculatus had different stages. Logistic growth curve was fitting the growthchanges, with determination coefficient above 0.95. Height and diameter growth of seedlings could be divided into 4 stages with nearly similar date.Root-shoot ratio decreased indicating underground growth increased while aboveground growth decreased. Leaf area ratio and leaf area root ratiodecreased and then increased. There was a significant positive correlation among ground diameter and main root length, total plant leaf area,aboveground biomass, underground biomass , the total plant biomass(r >0.92，P＜0.01). Significant negative correlation existed among root-shootratio and height, ground diameter, total plant leaf area, main root length, aboveground biomass, underground biomass, the total plant biomass.Significant positive correlation between aboveground biomass, underground biomass, and the total plant biomass was observed(r＞0.97，P＜0.01).