A field experiment was carried out to study the effects of three chemical agents(including water-retaining agent,FA Handilong and mixture of CaCl2 and GA) on soil moisture content of plough player and water relation of winter wheat under different irrigational conditions at later growth stage in subhumid zone.The results showed that water-retaining agent and FA Handilong had better effects on increasing the soil moisture content of plough player,flag leaf water potential and leaf WUE,especially the water-retaining agent.In contrast to CK,the average value of soil moisture content and leaf water potential under water-retaining treatment after flower stage was increased by 9.7% and 10.8% individually under irrigating twice,while it was increased by 5.3% and 7.4% individually under no irrigation in the experiment.The mixture of CaCl2 and GA could significantly decrease rangeability of daily change of leaf water potential and WUE.By regression analysis,soil water potential determined the leaf water potential,meanwhile there was a positive correlation relationship between leaf water potential and leaf WUE.The results also showed that all these three chemical agents had different way to improve yield of winter wheat,but water was the critical factor on yield in this experiment.Under the same irrigational condition,there was no variance in yield or ears number among four treatments,but under the different irrigational conditions,the variance of yield was dramatic.