Abstract: To further enhance the safety and stability of the XLPE insulated polyvinyl chloride sheathed copper power cable (YJV-0.6/1 kV 4×120), the material, structure and other parameters of the YJV-0.6/1 kV 4×120 power cable was optimized. The performance of the cables before and after optimization was tested by insulation thermal extension, insulation thermal shrinkage, sheath weight loss at low temperature, and low temperature stretching tests. The results show that before and after the optimisation of YJV-0.6/1 kV 4×120 power cable insulation and sheath material insulation thermal extension, insulation thermal shrinkage, sheath weightlessness and low-temperature tensile and other test parameters results were in line with national standards, in which the elongation under load was reduced from 64% to 40%, the permanent elongation after cooling was reduced from 6% to 0%, shrinkage was reduced from 2% to 1%, the sheath weight loss was reduced from 0.67 mg·cm⁻² to 0.45 mg·cm⁻², the depth of the indentation was reduced from 34% to 22.5%, and elongation at break increased from 135% to 180%. The test results verified that the overall optimization of the cable improved the stability and safety of the YJV-0.6/1 kV 4x120 power cable, further promoting the technological upgrading of the wire and cable industry.