Objectives:To evaluate the effects of 2-(3,4-dichlorophenoxy)triethylamine(DCPTA)on growth and photosynthetic capacity of maize seedlings exposed to simulated drought stress [(polyethylene glycol(PEG)-simulated] and to explore the promotion mechanism of DCPTA under drought stress.Methods:We pre-treated the maize seedlings of three leaves stage by addition of DCPTA to the hydroponic solution for 24h,exposed to simulated drought stress [15%polyethylene glycol(PEG)-treated] subsequently and scored growth and stress response phenotypes.Results:DCPTA pre-treatment induced drought tolerance increase during subsequent exposure to drought stress.It was evidenced by seedling growth(fresh weight,dry weight of shoots and roots,total leaf area,LRWC,root activity,contents of O2·-,H2O2 and MDA)and photosynthesis traits(photosynthetic pigments contents,Chlorophyll fluorescence parameters,gas exchange parameters,photosynthetic enzymes activities)of maize seedling,which were associated with decrease in ABA content and increase in IAA,GA,ZR contents.DCPTA application also improved the seedlings performance under well-watered conditions.15 and 25mg/L were the most effective concentration under well-watered condition and drought stress,respectively.?Conclusions:DCPTA improve growth and photosynthetic capacity rely on promotion of water absorption by root through regulation of plant hormones in coping with the drought stress in maize seedlings.