Abstract: To achieve low-damage and efficient directional cutting of rock masses, a directional splitting blasting cutting technology based on an in-hole prefabricated composite structure is proposed. The construction procedure and directional rock-breaking mechanism are described, and its cutting performance is compared with that of conventional presplitting blasting through numerical simulation and preliminary model tests. The results show that: The in-hole prefabricated composite structure produces a significant energy-focusing effect on explosive shock waves. Its special geometric configuration can directionally concentrate energy in space, thereby inducing directional rock splitting along the preset cutting direction; Numerical simulation results show that the in-hole composite structure produces significant stress concentration and a focused jet of detonation products in the cutting direction. The peak borehole-wall pressure in the cutting direction is 2-3 times that in other directions, whereas the blasting vibration velocity in the non-cutting direction is reduced by 48%. Compared with conventional presplitting blasting, the directional splitting blasting can achieve inter-hole crack penetration under a lower linear charge density and effectively suppress crack development in the non-cutting direction; Both the linear charge density and tip angle affect the main-crack propagation capability and the borehole damage range in directional splitting blasting. Parameter selection should balance the directional crack formation and damage control of the retained rock mass; Preliminary model test results indicate that the in-hole prefabricated composite structure can induce inter-hole cracks to propagate along the preset direction, verifying the feasibility of this technology for directional crack formation. These results provide a technical reference for contour blasting excavation of rock masses and resource utilization of excavated materials.