Abstract: For the situation that miss-fire accidents happen occasionally in mine blasting operation, in order to prevent the occurrence of blasting accidents in coal mines, based on the theoretical research of initiation condition, detonation current and firing energy of blasting serial network, the cause of miss-fire accident is analyzed. The results show that the main reasons for the underground miss-fire are the quality defect and electrical nonuniformity of detonator, the mismatch of detonating equipment and the excessive network resistance. According to the miss-fire causes of blasting net, the preventive measures which are in accordance with the actual situation of coal mine are proposed from the aspects of detonators, exploders, blasting network and blasting techniques.