According to the air temperature data recorded by the 83 meteorological stations along the middle and lower reaches of the Yangtze River from 1961 to 2012 and the data of single harvest rice planting area and yields in 136 counties within the region,this paper analyzed the spatiotemporal variation characteristics of the occurrence frequency of singl-harvest rice heat injury,and conducted risk assessment for the injury. Results showed that,in the past 52 years,the inter-annual variation of all levels of damage occurrence frequency along the middle and lower reaches of the Yangtze River took an open - top parabola shape. From 1980 to 2012,the total frequency increased at a rate of 14.10 times /10a. In terms of the region with high temperature damage,Hubei,Hunan and Jiangxi provinces suffered from the widest and the most serious damage,while in Anhui and Zhejiang Provinces,the damage was lighter,and Jiangsu Provinces damage was the least and the slightest. The probability of heat injury was relatively high in the south of Jiangxi and Hunan provinces,which reached 40% or higher. The high - value region of heat injury loss located in Badong of Hubei Province,Hengyang of Hunan Province and Jian of Jiangxi Province, which ranged from 10% to 14%. The risk degree of the high temperature damage is relatively higher in the southern part of Jiangxi and Hunan provinces,with a maximum of 0.36 in Hengyang,Hunan. Under the background of global warming,the risk degree of single - harvest - rice high temperature damage will continue to grow.