Abstract: The experiment was conducted with winter wheat CV．Jingdong 6 in PVC pipe and under rain free condition．It is indicated that all the distribution of ³H₂O in roots and flag leaf，characteristics of vascular bundle in primary roots and internode below ear，roots validity，transpiration rate and stomatal impedance of flag leaf are changed by water stress after flowering．The treatments of seed coating and foliage spraying at early jointing stage using Beinong 6(HK6)，a plant growth regulator，are proved to release and compensate the harmful effects of water stress．Both the area of vascular bundie in primary roots and internode below ear are increased by HK6，while the roots validity and the ability of water absorption and transportation are promoted． In flag leaf，stomatal impedance is changed to maintain the transpiration rate and the water use efficiency of single wheat plant is higher．The rate and ratio of ¹⁴C assimilates expo rted from flag leaf are increased by the chemical regulation．