Abstract: Three-year-old ‘Cabernet Sauvignon’ grape was used as experiment material,three treatments of without water stress,moderate water stress and heavy water stress were adopted by controlling the amount of irrigation and the degree of stress was reflected by leaf water potential（Ψ_b） before dawn,the sugar content and related metabolic enzyme activities in the base（leaf 1）,the underneath（leaf 2）,the middle（leaf 3）,the middle-upper（leaf 4） and the upper（leaf 5） leaves of ‘Cabernet Sauvignon’ young sprout were analyzed,in order to study the effect of water stress on sugar content and related metabolic enzyme activities in leaves of ‘Cabernet Sauvignon’ at different leaf ages.The results showed that under moderate water stress,the sucrose and soluble sugar content of different age leaves were higher than those of the control,and the reducing sugar content in the early stage was lower;the reducing sugar content in the middle and late stages was higher than control.Under severe water stress,the sucrose content of grape leaves at different ages was lower than control,and the reducing sugar content was higher than control.In the early stage of treatment,the soluble sugar content of leaves 3-5 was higher than control,and the soluble sugar content of leaves at different ages in the later stage was gradually lower than control.Moderate water stress could increase the sucrose phosphate synthase（SPS） activity of leaves 3-5,while severe water stress reduced the sucrose phosphate synthase（SPS） of leaves with different ages;water stress could increase the neutral transformation of leaves 3-5 enzyme（NI） activity,sucrose synthase（SS） and acid invertase（AI） activities of leaves at different ages.Moderate water stress was beneficial to the accumulation of sugarand the improvement of related metabolic enzyme activities in different age leaves.