Abstract: Amidst the backdrop of rapid advancements in power electronics technology,this study focuses on investigating the impact of SiO₂ insulating coatings on the core loss characteristics of nanocrystalline magnetic cores. A uniformly distributed and smooth SiO₂ insulating coating was successfully formed on Fe_73.5Si_15.5B₇Nb₃Cu₁ nanocrystalline ribbons via the solgel method,demonstrating strong adhesion to the substrate surface. After transverse magnetic annealing,the Fe_73.5Si_15.5B₇Nb₃Cu₁ nanocrystalline cores coated with SiO₂ insulation exhibited significant improvement in high-frequency loss performance compared to uncoated counterparts. Under 0. 2 T/100 kHz conditions,the coated cores with a ribbon thickness of 12-14 μm achieved an 18.2% reduction in specific total core loss,while the coated cores with a ribbon thickness of 20-22 μm showed a 24.3% loss reduction. Furthermore,the SiO₂ coating enhances core impedance values,effectively suppressing eddy current losses and thereby reducing the specific total core loss at high frequencies.