By using GIS(Geographic Infiomation System) to analyze recent environmental changes and associated human impacts in Honghu Lake over the last four decades，some preliminary results of the study are presented as follows:1. the reduction in lake surface area was resulted from hydrological engineering， agricultural reclamation and swamp formation (paludification);2. the development of emergent mecrophytes in the lake was under recent policies of lake resource use and management. PC ARC/INFO was used as the main GIS software running on an IBM一386 compatble micro-computer to automate，manipulate，analyze and display geographical data，mainly from remote sensing images and landform maps. The environmental effects and processes under human activities, by means of embankment，subd ivision，reclamation and water level control， were successfully displayed and documented. It illustrates the value of GLS in environmental monitoring，assessment and managenent.