Abstract: Taking 8 major and particular major accidents of explosives spontaneous combustion in underground coal mines from 2005 to 2014 as samples, the paper studied unsafe acts from reasons occurred and expanded. Unsafe acts that causing the accident can be divided into 5 big kinds including storing explosives illegally, producing illegally, poor management, purchasing and using non-permissible explosives, without equipping professional technicians or off-site, and 17 small kinds, totaling 52 ones. Purchasing and using non-permissible explosives as well as storing explosives illegally occurred most frequently and were the direct unsafe acts. Unsafe acts that expanding the accidents can be divided 4 big kinds including poor self-help, poor rescuing, poor ventilation system, others, and 41 small kinds, totaling 41 ones. The absence of self-rescuer (without giving or bring) and delaying the rescue or rescuing improperly occurred most frequently. The line workers’ unsafe acts that did not include direct unsafe acts were fewer than those of the managerial personnel, so coal mine enterprise should strengthen the training for them in accidents prevention.