Abstract: The regional environmental system influenced by human-earth interactions is a complicated multiplex system including society,economy and environment. A good many environmental problems in the system are very perplexing,and therefore there are lots of uncertainties in environmental decision process.Environmental decision support system(EDSS) can assist the environmental decision-makers to make environmental decisions more scientifically and effectively.The progress of EDSS’s application in the past 30years in China and other countries were reviewed including in water environmental planning and management,atmosphere environmental quality management,city solid waste management,and so on.The application in environment impact assessment(EIA) was analyzed as a major area by some cases.EDSS,which has strong data upgrading ability and two major functions of environmental quality analysis and prediction,is an effective tool to solve the perplexing problems in EIA.Based on the development in recent years,EDSS would make great progress in virtue of new technologies,such as artificial intelligence(AI),3S and multimedia.It would play a more significant role in environmental planning and management and EIA,etc.in the future.