Abstract: In order to solve the problems such as large amount of coal lost in goaf, high air leakage rate at the end, high concentration of floating coal between supports and roof areas, and gas index over-limit in abnormal fire area of No.3-5 composite coal seam in Madaotou Coal Mine during fully mechanized caving mining, the technologies of nitrogen injection in goaf, chemical retardant spraying between supports and rear roof area, grouting in abnormal fire area and end sealing were studied. Through the experimental study in 8210 full-mechanized caving mining face, application effect showed that, in mining period, the temperature control of the mined-out area, working face and supports between was within 30 ℃, CO gas is always kept below 24×10^-6, and representative gas such as C₂H₄ and C₂H₆ has ever appeared. The fully mechanized caving face can safely and efficiently complete mining.