The uniaxial compression failure mechanism of jointed rock mass with cross-cracks was studied through similar material uniaxial compression tests and numerical computation with Abaqus. The study results show that when the angle between the main crack and loading direction is at 35° or 45°

the main crack is the key crack of crack propagation and rock mass failure. At these cases the strength of rock mass with cross-cracks is higher than that of rock mass with single crack. The reason is that the maximum hoop stress σθmax of main crack tip is less than that of single crack. When the angle between the main crack and loading direction is at 0° or 90°

the secondary crack is the key crack of crack propagation and rock mass failure. When the angle between the main crack and loading direction is at 0°

the maximum hoop stress σθmax and the maximum stress intensity factor KⅡmax of most secondary cracks are higher than those of single crack. So at these cases the strength of rock mass with cross-cracks is lower than that of rock mass with single crack. The KⅡmax of the case with 45° between main crack and secondary crack is the maximum stress intensity factor in those cases that the angle between the main crack and loading direction is at 90°. So the strength of rock mass with 45° between main crack and secondary crack is the lowest one in this case group.