Based on the single fire-fighting technology application effect was limited, It was difficult to effectively control coal spontaneous combustion in the process of working face advancing. To protect the safety of productive process in B901 fully mechanized caving face of No.4 Mine in Saier, based on the actual situation of B901 working face, the comprehensive fire-fighting technology of B901 working face was studied. The fire-fighting technology of nitrogen injection, inhibitor, grouting was raised and designed. Through the duct monitoring analysis, it was found that CO concentration the of B901 working face return airflow corner in exploitation process was under 10×10-6, which ensured the safe mining of B901 working face.