This study introduces the fabrication of dual-layer composite nanofiber membranes incorporating AG80 (tetrafunctional epoxy resin), BN (boron nitride), and PI (polyimide) through electrospinning, with the aim of overcoming the limitations of conventional polyimide (PI) materials in thermal management and electrical insulation for flexible circuit boards. Although PI is recognized for its mechanical strength, chemical stability, and insulating properties, its low thermal conductivity, brittleness, and complex processing challenges limit its broader application. By precisely controlling the composition of AG80, BN, and PI, and optimizing electrospinning parameters, we successfully developed a nanofiber membrane that exhibits enhanced thermal stability and insulation properties. The resultant membrane demonstrates remarkable flexibility, retaining mechanical integrity after 10,000 bending cycles, and achieves a high thermal conductivity of 1.42 W/m<middle dot>K. Optimized porosity further enhances surface adhesion, rendering it ideal for high-performance flexible circuit boards. These findings provide valuable theoretical and practical insights for the design and development of advanced flexible electronic devices.