It is important for current practical electronics to run faultlessly in a good operating temperature because the electronic components (ECs) are not designed to work better at very low temperature, especially in cold climate and high-altitude zones. Herein, we designed and fabricated a conductive composite consisting of graphene oxide (GO)/carbon nanotube networks (CNTs) and polyethylene glycol (PEG) to fast supply heat through ECs even if at low temperature environment in future. The GO/CNTs/PEG composites afford a lot of conductive pathways by CNT networks with high conductivity and hold phase-change latent-heat material PEG for thermal energy storage and release, which permit self-heating of the composites through Joule heating generated by the low voltage across them. Therefore, the obtained composites may play an important role in thermal management applications for preheating effectively ECs to achieve desired performance and life cycle in the cold climate, etc.