The failure process of rock in uniaxial compression tests is simulated by using the particle flow code(PFC). Fish language embedded within PFC2D is used to generate random imperfections and to develop the rock numerical specimens with different homogeneous degrees. The results show that inhomogeneous degree has great influence on characteristics of acoustic emission in rock. With the increase of inhomogeneous degree

peak strength of rock specimens decreases and the total number of AE increases greatly. The spatial distribution of AE becomes more extensively. Meanwhile

AE of rock samples appear earlier and sustain for longer duration. The intensity of AE after the peak failure retains higher level. The maximum intensity of AE under uniaxial stress state lags behind the peak damage to different extents. With the increase of inhomogeneous rock

the hysteresis effect of AE becomes obvious which suggests that rock failure appears earlier than the maximum intensity of AE.