Abstract: According to the special mining technique of the fully mechanized top coal caving mining, the paper analyzed the float coal deposit status in the goaf.Th e coal caving zone in the goaf of the fully mechanized top coal caving mining face was divided into three zones from top to bottom, as the coal rejects zone, the coal rej ect and left coal mixed zone and the left coal zone. The paper provided that there would be three spontaneous combustion zones in the strike of the coal mining face an d the vertical height of the goaf.The paper provided the conclusion that the organic combination of the three zones in the two directions would form the three room spon taneous combustion zones in the goaf of the fully mechanized top coal caving mining face. Thus the conception of the three room spontaneous combustion zones was pr ovided.Based on the analysis on the coal spontaneous combustion conditions, the oxygen density and the left coal distribution were determined as the division index of the three room spontaneous combustion zones. The division standard of the three room spontaneous combustion zones was set up and could be applied to divide the ac tual goaf of the fully mechanized top coal caving mining face.