Cathodic plasma electrolytic oxidation (CPEO) is a novel oxide coating fabrication technology developed on the basis of plasma electrolysis in liquid. The Fe-based and Ti-based metal cathodes can be quickly oxidized under liquid phase discharge, which improves their wear resistance and corrosion resistance. It is believed that the CPEO technology is a breakdown for conventional knowledge in the plasma electrolysis field. Compared with anodic plasma electrolytic oxidation, namely microarc oxidation, the CPEO technique has much high growth rate of oxide coating and meanwhile it may be also applied to the surface modification of all kinds of Fe-based materials. The basic principle of CPEO technique was introduced, including the evolution of liquid phase discharge phenomenon, voltage and current, the formation and breakdown process of vapor gas envelope (VGE), the near-surface temperature in the cathode under different voltages and the rapid oxidation process of cathode. Furthermore, the similarity and difference among the CPEO technology and anodic plasma electrolytic oxidation and plasma electrolytic saturation were compared. In addition, the detection of optical emission spectroscopy during the CPEO discharge process and the corresponding calculation of plasma parameters such as plasma electron density and electron temperature were also introduced, and then the growth mechanism of CPEO oxide coatings at cathodic discharge environment was discussed. On the other hand, the morphology, microstructure and properties of CPEO coatings on metals such as low-carbon steel, high-carbon steel, stainless steel, molybdenum and TiAl alloys were summarized. The carbon particle property suspended in electrolyte solution was analyzed, and the possibility for synthesis of diamond-like carbon component during VGE discharge process was discussed. It was found that the DLC-containing CPEO composite coatings on metals could be fabricated under liquid phase discharge in glycerin and urea solutions. Finally, the development direction and potential application of cathodic plasma electrolytic oxidation technology were summarized and prospected.