Abstract: Based on the data of the meteorology and cotton yields,the meteorological indexes for the estimation of low temperature injury of cotton from sowing stage to blooming stage in Xinjiang Autonomous Region were studied preliminarily.The results showed that the cotton yields were likely to reduce in term of the pattern of the climatic year,as the departure of average temperature in June in Northern Xinjiang was with ≤-0.5℃,the temperature in May and June kept a continuous low and the departure of average temperature was with ≤-0.5℃ in Southern Xinjiang,or as the blooming stage delayed,such as delayed over five days in Kashi,and over three days in Shihezi,Bozhou,Bazhou and Akesu arrears,or as the departure of average temperature from June to August are between 0 and-0.4℃ and the departure of average temperature within at least tow months was negative.The cotton yields were likely to reduce seriously,as the departure of average temperature from June to August was below-0.5℃ and the monthly departure of average temperature from June to August was negative.

Key words: Yield reduction year of climate, Yield reduction year of climate, Low temperature injury, Meteorological index