The Suganhu wetland is located in the inland basin at the intersection of the Altun Mountains and the Qilian Mountains in the northwest of the Qaidam Basin. It is a sensitive area of global climate change, and its vegetation coverage plays an important role in the formation of the ecological environment of the Suganhu salt marsh. Study of spatial and temporal heterogeneity evolution is helpful to understand the structure function and environmental response mechanism of wetland community. By the survey of wetland flora, this study estimated vegetation coverage of Suganhu wetland from 1987 to 2017 based on Landsat data, and analyzed the variation pattern of vegetation coverage of each level at Suganhu wetland and its influencing factors. The results showed that the dimidiate pixel model had high accuracy in the study of vegetation coverage of inland salt marsh. The vegetation coverage of the Suganhu wetland showed an overall upward trend between 1987 and 2017, which was positively related to temperature and precipitation, and the correlation between precipitation and vegetation coverage was greater than that of temperature. The spatial vegetation coverage positively correlated with the depth of the groundwater depth and negatively correlated with the total salinity of the soil. But the correlation between the vegetation coverage of different grades and the depth of the groundwater and the total salinity of the soil was different. The vegetation coverage of the Suganhu wetland was affected by the depth of groundwater and the spatial heterogeneity of the soil's total salt content,which presented patchy Mosaic distribution.