<p>Despite their excellent mechanical properties, carbon fiber (CF) suffers from insufficient intrinsic electrical conductivity, which limits their application in composites requiring high conductivity. In this study, PAN/MTP blended carbon fiber yarns with different MTP loadings were successfully fabricated via electrospinning, enabling a systematic investigation of how varying pitch contents (0–20 wt%) regulate the electrical conductivity and microstructure of the yarns. Raman spectroscopy, XRD, and SEM characterizations reveal that an appropriate amount of pitch achieves pore defect repair via pore-filling induced by its MTP-driven melting–softening–flowing behavior, while promoting the growth of graphite microcrystals, thereby constructing a high-efficiency conductive network. Results indicate that the electrical conductivity first increased and then decreased with increasing pitch content. The maximum conductivity of 16.7 S/cm was achieved at a pitch addition of 10 wt%, representing a 50% improvement compared to pure PAN-based yarns. This study successfully prepared pitch-modified conductive CF yarns, improved their conductive properties, and explored the underlying conduction mechanisms. It provides a theoretical basis and technical guidance for the application of low-cost, high-performance CF yarns in flexible electronics and other fields.</p> Graphical abstract <p></p>