Abstract: The general polder is a unique polder form of Dongting Lake.However,with the development of social economy,the flood control protection objects of various general polders are quite different.It is urgent to further determine the classification of general polders in Dongting Lake during the flood control zoning,so as to formulate appropriate flood control measures.Using the geometric transformation of GCT graph,combined with population density,number of people protected by levees per kilometer,levee grade,flood storage loss,cultivated land area and importance parameters,Establish a model for judging the shape similarity of flood protection areas and flood storage and detention areas of general polders,230 general polders in Dongting Lake area were divided.The parameters of the 6-dimensional radar map of the reference value of the flood protection area are 900 people/km~2,0.46 people/km,Grade 2 embankment,32 yuan/m~3,666.67 hectares of arable land,2 points for importance.The parameters of the 6-dimensional radar map of the reference value of the flood storage and detention area are 600 people/km~2,0.18 people/km,Grade 4 embankment,32 yuan/m~3,66.67 hectares of arable land,1 point for importance.Use Matlab to normalize the data,divide the 6 parameters of each general polders into dimensionless ones within the range of 1～5,and draw a 6-dimensional radar map.At the same time,the similarity judgment of the 6-dimensional radar map with the reference value of the flood protection area is completed,and the judgment result is general polder that is not similar,continuing to determine the similarity with the 6-dimensional radar map of the reference value of the flood storage and detention area.If it is still not similar,it will be determined as a flood area.The results show that there are 67 flood protection areas,53 flood storage and detention areas and 110 flood areas.Through a further analysis of the results,suggestions on model modification and subsequent general polders planning are put forward.It serves as a reference for the division of flood protection area,flood storage and detention area and flood plain to be carried out in the general polders of Dongting Lake Area.