Abstract: Based on microseismic monitoring of special igneous rock at 762 working face of Haizi Coal Mine, the article analyzed microseismic activity law of deforming and breaking of special igneous rock. The results show that microseismic activity under igneous rock is mainly with low power shock, 0 to 200 J accounted for 83.1%，which will not cause the roof impetus threat during mining; breaking pattern of igneous rock is layered, not holistic; the spectrum feature of igneous rock's ruptured microseismic signals are lower amplitude, shorter duration time, faster attenuation; main frequency is about 0 to 200 Hz, the main frequency presents "double peak" phenomenon around 50 Hz and 150 Hz. With above rules, failure and deformation of similarity conditions igneous rock can be monitored and predicted effectively.