The colony structure of red imported fire ant,Solenopsis invicta Buren in winter,in Wuchuan County,Guangdong Province,was studied in this paper.The proportion of workers was about 96.3 % in the colony.Larval was the majority in brood of the colony.There were 287 and 24 ants in area of 1 cm^2 mound surface base and volume of 1 cm^3 mound respectively.The relationship between the mound surface base area,the mound volume and the colony number were studied.14 models were constructed and used to describe the regulations of the colony.In general,the colony in winter was more larger than that in spring when the mound sizes were same.Based on the above results,the method which could be used to determine the quantity of red imported fire ants in the certain area was suggested.