By spraying Multi function drought preventing agents onto winter wheat,photosynthesis was increased by 14～28 percent compared with that of the natural plot. Stomata resistance was increased by 24～51 percent. Transpiration was decreased by 1～9 percent. Water use efficiency was increased by 2～27 percent. The weight of 1000 grains of winter wheat and yield were raised by 2～6 and 2～7 percent respectively. These indicate that the multi function drought preventing agents have the function of promoting growth,decreasing transpiration,and raising yield for winter wheat.