In recent decades,the desertification of the Zoige Plateau showed a significant growth trend,which is threatening the grassland ecological environment. Using ENVI and ArcGIS processing the Landsat(19902016) is to quantify the trend of desertification in Zoige Plateau,as well as desertification causes in different regions. Based on indexes of NDVI and Albedo,the classification of desertification grade was built to obtain the temporal and spatial distribution of desertification and desertification gradation. Results showed that the area of desertification increased at the rate of 2.17 km~2·a~(-1) in 19902016. From 1990 to 2004,the main change was the area of mild and severe desertification and the change rate was 1.27 km~2·a~(-1) and 1.36 km~2·a~(-1),respectively. From 2006 to 2011,the changing trend of desertification was reversal,and the total area of desertification decreased by 33.44% in 7 years,with slight desertification decreasing at the fastest rate of 2 km~2·a~(-1). The total area of desertification increased by 58.43% in the period of 20112016,with mild and severe desertification increasing by 2.59 km~2·a~(-1) and 4.04 km~2·a~(-1). The spatial distribution and expansion of desertification was as follows: the edge of the peat swamp around the northern part of Cairima township,the river floodplain and mid-channel bars along the river,the peat swamp on southwest of A'xi township,along the edge of the peat swamp in northwest of Zoige County,about 12.8~18 km away from the southern and southwestern direction of A'xi township. Due to desertification controlling measures,desertification occurred changeover in the short term,while it still showed rising tendency overall. The internal causes of desertification expansion in the region are that there are the loose and fragile deposits and fine lake sediments below the ground surface. External causes is wetland shrinkage and degradation caused by climate change and excavated ditch drainage,as well as intensive human activity(e.g.,over-grazing) on surface vegetation deterioration.