Abstract: Dongting Lake is the second large fresh water lake of China.Reedsgrow thickly and luxuriantly on a great tract of banks and shores of therivers and lakes.Rather satisfactory results of determining the extent ofreed distribution,calculating its size,growing and yield,and developingreed distribution diagram,through Landsat images analysis,aerial surveyand field investigation,are obtained.In the Landsat false eolour composite images and MSS₇,the colourand grey stage of reed resources and those of ground objects surround themare quite different,the demarcation lines are clear,and images are noti-ceable.According to study and interpretation,the reed-growing area ofDongting Lake amounts to 937,500mu.Rough estimates of reed productionbased on the break up of density,the figurative analyses of the images ofLandsat MSS₇ made by computers,and the data sampling of the fieldsurvey of per-unit yield are rational.Estimates show that the reed pro-duction of 1980 of Dongting Lake area will come up to 600,000—630,000tons.