In order to study the effect of stress interference on the synchronous propagation of multiple prefabricated cracks in shale under the action of high-voltage electrical pulses in water, the change law of crack propagation trajectory, propagation length, average width, deflection angle, and equivalent stress distribution between cracks was studied, the effects of crack angle, crack number, horizontal ground stress difference and other factors on crack initiation and propagation were comprehensively considered. The triaxial high-pressure pulse hydraulic fracturing test platform was used for laboratory fracturing test and extended finite element method(XFEM) numerical simulation calculation, the pore and cracks analysis system(PCAS) crack analysis software was used to analyze the geometric characteristics of cracks. The results show that under the action of high voltage electric pulse in water, the pre cracks start and expand along the radial and axial directions. The larger the included angle between the radial double cracks is, the weaker the interference between the cracks is, and the worse the crack propagation effect is. Three radial cracks with equal included angle propagate, and the middle crack is the most disturbed and restrained by stress, while the three radial cracks with unequal included angle propagate, and the right crack far away from the middle crack is the least disturbed and the propagation effect is the best. With the increase of the horizontal in-situ stress difference, the stress interference 9 between cracks is enhanced, and the crack propagation effect is gradually weakened. The research results can provide a certain reference for analyzing the process and laws of multiple prefabricated cracks propagation in shale under the action of high-voltage electric pulses in water. parts. In the later stages, as the cavity expands, the main effect is dissolution, and the rate of cavern construction is high. The cavity mainly expands towards the middle and upper parts. The research results and rules provide a certain theoretical basis for cavern construction design in field, and have guiding significance for improving construction efficiency and optimizing parameters.