Abstract: Aims to investigate the effects of coronatine(COR) on physiological parameters in wheat (Triticum aestivum L.cv Chuangwu 134) flag leaves under heat stress was studied.The results showed that under heat stress conditions,the flag leaves treated with 0.1 μ mol/L COR could maintain high relative water content,and keep the integrity of cell membrane by decreasing membrane damage;Meanwhile,COR could increase the capacity of photosynthesis of the flag leaves,increase thousand kernel weight by 9.1%,and increase the theoretical yield by 495.75 kg per hectare and consequently reduce the production loss causing by heat stress.