Abstract:Based on the daily temperature data of Yunnan province during 1960 to 2009, the rice chilling process was extracted and graded for recent 50 years according to the operating guideline of rice chilling damage in period of head sprouting and anthesis in Yunnan province.The frequency distribution of rice chilling damage in each decade was drawn by ArcGIS, then the chilling damage strength characteristics was studied geographically.The methods of linear trend and cumulative anomaly curve were used to reveal the evolution features of rice chilling damage in period of head sprouting and anthesis in Yunnan province in recent 50 years.Results showed that the rice chilling damage mainly occurred in Zhaotong, Qujing and Baoshan's Longling county, with Zhaotong as the most injured city.Generally, the total days of rice chilling damage showed a decreasing trend for the past 50 years.However, analysis of the ratio of stations with rice chilling vs.total stations and cumulative anomaly curve indicated that the 1970s had rice chilling damage with the largest range and the highest frequency, while the 1990s had the least rice chilling damage, then chillings occurred intensively in years after 2000, and eventually decreased in 2008.