Abstract: To study the relationship between the pre-splitting blasting effect and the decoupling coefficient and unidirectional load, based on the field test of a new mining face in a mine, the ground stress was simplified as the unidirectional load in the vertical direction, and the LS-DYNA software was used to simulate blast holes with diameters of 73, 89, 94, 104, and 130 mm were carried out to simulate the pre-splitting blasting crack propagation process, the influence of unidirectional load on the crack propagation, the relationship between the presplitting effect and the decoupling coefficient. The study results show that under the action of a unidirectional load perpendicular to the axial direction of the blast hole, the blasting crushing zone and the length of the main crack are not affected by it, and the tip cracks can achieve secondary extension; when the decoupled coefficient is between 1.14 to 2.03, the energy consumed to form the crushing zone is less than 20% of the total explosion energy; the comprehensive explosive energy utilization rate and pre-splitting effect, the pre-splitting effect is best when the decoupling coefficient is near 1.63.