The partial discharge detection method has been widely used in evaluating the insulating property of AC electiric equipments. However, the research on partial discharge detection under DC voltage is still at the primary stage. Some useful analysis methods under AC voltage cannot be applied to the DC voltage situation because of lack of the phase angle conception. The research status domestic and abroad is summarized in this paper, the physical model and the influence of temperature and some other factors on partial discharge under DC voltage are introduced. Some common ways to analyze partial discharge under DC voltage are also summarized, and typical test cases of partial discharge of DC cables are analyzed.