The insulation on-line monitoring and fault diagnosis for high voltage power equipments is one of the most important techniques to maintain the reliability of power system. Since 1990s, the insulation on-line monitoring and fault diagnosis techniques have been greatly developed in China. Many universities, companies and research institutes have made great effort in this field. In this paper, the progress in China with the respects to partial discharge (PD) detection methods, on-line calibration, interference suppression, and fault diagnosis are reviewed.