In order to study the influence of initial crack geometrical properties on rock crack propagation, the influences of crack length and crack spacing without double crack on crack propagation under the specific stress states are investigated using numerical analysis of rock failure RFPA. Using this method, the phenomena of crack initiation and propagation are well reproduced. Crack propagation characteristics under the specific stress states are obtained based on a large number of numerical tests. Rock failure processes are also described. This work provides a useful theoretical reference for studying rock crack propagation characteristics.