During last few years, large number of papers published on direct current glow discharge plasma (GDP) in and in contact with liquids due to the increasing interest for its application for wastewater treatment. In this paper, recent progress of GDP on wastewater treatment has been systematically reviewed, covering the degradation of organic pollutants, the reduction of Cr(VI) and the inactivation of algae. This contribution also provides comprehensive insights into reactors, generation mechanisms, physical characteristics, influence of operating parameters and energy efficiency comparing with other AOPs. The emphasis in this paper is on the mechanism of the removal of hazardous chemicals induced by GDP and the combined process. It ends by shortly mentioning theoretical fundamentals and promising actual application of GDP which call for further study. (C) 2012 Elsevier Ltd. All rights reserved.