Abstract: High-voltage electric pulses (HVEP) technology demonstrates potential for enhancing the efficient extraction of coalbed methane. However, current experimental devices lack the capability to accurately observe the fracture evolution of coal under load during HVEP treatment, especially under true in-situ stress conditions. This limits the evaluation of its engineering effectiveness. To address this issue, a non-destructive observation and permeability enhancement test device for HVEP-induced in-situ coal seam fracturing was independently developed. The device features a ray-penetrable pressure chamber at its core and integrates four functional modules: servo loading, gas seepage, high-voltage discharge, and data acquisition. Its main features include: enabling in-situ CT scanning of loaded coal before and after HVEP fracturing, accurately characterizing fracture development under geostress conditions. Supporting single discharge energy of up to 100 kJ, enhancing energy input. Applying 200 kN axial stress, 60 MPa confining pressure, and 30 MPa gas pressure, simulating the stress conditions of deep coal seams for HVEP-induced permeability enhancement research. Enabling real-time observation and data acquisition of coal deformation, stress conditions, gas flow, electrical signals, and fracture propagation. Using this device, in-situ CT scanning and seepage tests were conducted on loaded coal samples before and after HVEP fracturing under various discharge voltages, validating the device’s performance. The tests clarified the influence of in-situ stress on fracture morphology, quantified changes in three-dimension fracture parameters, and revealed the permeability enhancement effects of HVEP under varying discharge voltages. Experimental results show that under stress loading conditions, coal samples do not exhibit significant fragmentation following HVEP fracturing. However, upon removal of the in-situ stress constraints, the fracture tips tend to reopen, resulting in increased fracture pixel ratios and fractal dimensions. Consequently, the complexity of the real fracture network may be overestimated. Meanwhile, within the test’s voltage range, increasing the discharge voltage effectively promoted fracture propagation and improved post-fracture permeability. Under inlet gas pressures of 0.8 to 2.6 MPa, pre-fracturing permeability exhibits a V-shaped trend with pressure variation, while post-fracturing permeability decrease with gas pressure due to gas adsorption-induced coal matrix swelling.