 Carbon nanofibers, CNF, have become increasingly popular due to their unique physical and chemical properties. They can be used in a variety of applications, such as electrical devices, electrodes for batteries and supercapacitors, and sensors. Their electrical properties depend heavily on the dispersion and percolation of CNFs within the material. Percolation theory is used to explain how the electrical properties of CNF composites vary with different parameters, such as the aspect ratio, backbone structure, and fractal characteristics of the CNFs. Additionally, the thermal and mechanical properties of CNF composites are also discussed. Preparation methods include catalytic chemical vapor deposition growth and electrospinning, while preparation methods include melt mixing and solution processing. Finally, CNF composites are used as sensors and electrodes in various applications. This article was offered by Li Chaofeng, Ning Xia, and Jing Zhong.