Abstract: To achieve the effective monitoring of rock failure events in the mine water inrush inoculation process, a moment tensor inversion method based on digital seismology was introduced to process abnormal microseismic events monitored in Hebei Fanshan Phosphate Mine. The vibration displacement field in the mine scale could be expressed as the convolution of moment tensor and Green's function. The moment tensor was linearly inversed through extracting displacement data from the microseismic events and calculating the Green's function (pulse response of transmission medium between the source and sensors). Then, the type of ruptures was distinguished by analyzing the fracture azimuth of microseismic events. As a result, a 3D effect picture of the microseismic monitoring area was built to fit the rock failure surface, predict its development trend, and demarcate the water inrush danger zone preliminarily. Research results show that the moment tensor inversion method can be used to calculate a series of focal mechanism solutions and can reflect the rock failure in the mine water inrush inoculation pocess and development trend effectively.