Using the rock failure process analysis software-RFPA2D, we selected brittle granite as the object and carried out numerical crushing experiment under different loading rates, got the RFPA2D stress diagram and the acoustic emission diagram corresponding to the same loading. The results show that, compared to a single drill bit, the rock will form stress superposition inside when it is under dual drill bits, and the crack under the superposition of stress will impact on adjacent cracks, the crack tip can produce stress concentration, the crushing rock will release more energy and the counts of acoustic emission; with the increasing of loading rate, the total energy of acoustic emission and the vertical load released by the crushing rock will increase.