Abstract: In order to investigate the relationship between root activity and photosynthetic ability at different growth stages of Panax ginseng,the stem of P.ginseng was cut at the base and the root bleeding sap was collected.The root bleeding sap mass(m_BS), as an index indicating root activity,net photosynthetic rate (Pn) and the plant aerial organs absorbing water mass（AWM）of P.ginseng were measured at different growth stages.The results showed that m_BS was lower at flowering stage,higher at green fruit and early red fruit stages and the lowest at red fruit stage.The photosynthesis of leaf was lower at flowering stage,higher at green fruit stage and early red fruit stage and the lowest at red fruit stage.BSW was positively correlated with Pn,PC and AWM.In addition,Pn/m_BS and AWM/m_BS was the highest at red fruit stage.The root activity was closely related to leaf photosynthesis of P.ginseng at different growth stages.