Abstract: The characteristics of Yunnan climatic productivity variation and the effects of climatic variation on agricultural production in the past 50 years are analyzed, and the relationships between temperature, precipitation and wheat, rice yields are mostly studied. The results show that the precipitation during Dec. to Feb. of the next year is the key factor for wheat production and the cumulative temperature higher than or equal to 10 ℃ is more favorable for rice production than precipitation. Furthermore, the periods of major climatic disasters affecting grain production of Yunnan province are diagnosed. The main meteorological disasters for the crops sown in late autumn. are drought during Jan. to Feb. and cold of the late spring during Feb. to Apr. For crops sown in late spring, the main disasters are drought in May and chilling damage during Jul. to Aug.