Abstract: Circular samples with borehole are numerically loaded using flowcoupled Rock Failure Process Analysis code (F-RFPA2D) under internal hydraulic pressure rising at a constant rate under zero confining pressure to investigate the hydraulic fracture initiation, propagation and breakdown. Our findings are:heterogeneity of rock has a significant influence on initiation?breakdown pressure and irregular hydraulic fracture trajectory;hydraulic fracture initiation occurs considerably early before breakdown pressure is reached;the random location of the individual inhomogeneities results in an irregular hydraulic fracture trajectory.