From 2008 to 2009,we selected six main freshwater and brackish-water lakes in Inner Mongolia as study objectives to investigate the changes of these lakes and the impact factors for a fifty-year period since 1970s.Combined with Landsat image interpretation and field work conducted in 2008 and 2009,the study analyzed the dynamic changes of the volume and the water quality of the lakes.The results showed that Hulun lake ranked the first by the volume with a water volume of 52.1 * 108 m~3 .Hasu Lake was the smallest one with a water volume of 0.18 * 108 m~3 and was the only freshwater lake of the selected ones.The other five lakes were brackish water lakes.The salinity of Dalai Nur Lake was the highest among the five lakes,with a salinity of 0.6 g·L~(-1) .The hydrochemical composition of Dalai Nur Lake was Cl~- - Na~+ type which was same as those of Ulansuhai Nur Lake, Dai Hai Lake and Hongjian Nur Lake.The hydrochemical composition type of Hasu Lake was Ca~(2+) - Mg~(2+) - HCO_3~- - SO_4~(2-),while Hulun Nur Lake had a hyrochemical composition type as HCO_3~- - Na~+ .In general,the lakes changes in Inner Mongolia presented a similar characteristic over the last fifty years.The lake water levels gradually decreased.The areas of the lakes were shrinking.The volumes of the lakes decreased while the salinities of the lakes increased and vice versa.Long-term trend of lake water volume and quality had a significant correlation with regional climate change.However,the spatial-temporal movements of the different lakes varied due to human activities.In the last five decades,the water quality Hasu Lake was stable while the salinities of Hulun lake,Dai Hai Lake,Dalai Nur Lake and Hongjian Nur Lake were quickly increased.The water quantity of Ulansuhai Nur Lake was relatively stable benefited from the hydraulic constructions and agricultural irrigations.But the salinity of Ulansuhai Nur Lake obviously increased as well.