An investigation is reported on the characteristics of progressive failure of Hong Kong granite. Uniaxial compression tests are performed on a number of Hong Kong granite specimens with the MTS 815.04 testing machine. Acoustic emission signals are recorded to trace the evolution of damages. Parametric studies on the effect of grain size are attempted. The results show that the increase in grain size will reduce the brittleness during failure. In addition,discussion is extended to the grain size effect on the stress thresholds of crack closure,crack initiation and crack damage. The RFPA2D code is also used to observe the failure characteristics of brittle rocks such as granite. Microscopic tensile failure is dominant in the ultimate failure of all the uniaxially compressed models. The crack initiation threshold is also determined by the numerical approach. The failure of coarse-grained models seems more ductile.