Abstract: Polyimide/zinc oxide nanocomposites were systematically investigated for their dielectric properties and aging behavior in distribution network insulation applications. Polyimide samples with varying zinc oxide mass fractions were prepared via the solution casting method, including pure polyimide (PA0) and nanocomposites with 1% (PA1), 3% (PA3), 5% (PA5), and 7% (PA7) zinc oxide additions. Accelerated aging was conducted by applying 200 h of ultraviolet irradiation and direct current electrical stress to the samples using a customized aging chamber, and the sample performance evolution was monitored in real time. Surface morphology was observed by scanning electron microscopy, phase structure was analyzed by X-ray diffraction spectroscopy, and dielectric properties were evaluated through measurements of relative permittivity and direct current resistivity. The results indicate that the samples with 1% and 3% zinc oxide additions (PA1 and PA3) exhibit superior electrical stability during aging, characterized by smaller fluctuations in relative permittivity and higher direct current resistivity. Moderate zinc oxide addition significantly enhances the dielectric properties and aging resistance of polyimide nanocomposites. These findings provide a reference for the development of insulation materials for distribution networks and are of positive significance for improving power transmission reliability.