To investigate the association between droughtinduced carbon/nitrogen imbalance and leaf senescence,we treated eight maize varieties in leaf senescence progress under drought stress with PEG to mimic the drought stress.Leaf senescence symptoms,such as photosynthesis,photosystem II photochemistry efficiency (F_v/F_m) and chlorophyll content,and the nonstructural carbohydrates (soluble sugars,starch) content and nitrogen content were determined.Then,the correlation between droughtinduced leaf senescence and carbon/nitrogen imbalance (C/N ratio) was analyzed.Our results showed that:(1)the net photosynthetic of eight maize varieties were severely suppressed,F_v/F_m has fallen dramatically and chlorophyll content decreased significantly,which indicated that drought induced maize leaf senescence.(2)Drought stress induced the maize leaf senescence accompanied with the accumulation of soluble sugar content,slightly increased starch content,decreased of total nitrogen content and increased significantly of C/N ratio,carbon and nitrogen balance were damaged.(3)Both the nonstructural carbohydrates content and carbon/nitrogen ratio showed a significant negative correlation with chlorophyll content,and there was a significant positive correlation between total nitrogen content and chlorophyll content.Therefore,carbon and nitrogen metabolisms were tightly associated with droughtinduced leaf senescence,and the carbon/nitrogen balance may involve in the regulation of droughtinduced leaf senescence.