Vegetation plays an important role in global environmental change. Monitoring the dynamics change of vegetation coverage is critical to a region's ecological security. With the development of 3S technology, vegetation monitoring becomes more convenient and effective. This study used MODIS NDVI data of the month (June-September) when vegetation grew vigorously from 2001 to 2015 in northern slope of the Tianshan Mountains, combined with dimidiate pixel principle to extract the vegetation coverage. Linear regression, coefficient of variation and other methods were used for the analysis of vegetation coverage dynamics. The results showed that: (1) The annual average vegetation coverage in the study area ranged from 0.4 to 0.5 in June-September, while vegetation coverage grade were mainly at low and low-medium levels. (2) During 2001-2015, the vegetation coverage tended to increase gradually and the proportion of vegetation improvement area (54.42%) was larger than that of the degraded area (45.58%). The vegetation improvement was more obvious in the west than in the east. The variation types of vegetation coverage were mainly weak variation and moderate variation, and the major change type of vegetation coverage was stable type. (3) The change of vegetation coverage in northern slope of the Tianshan Mountains was obviously affected by altitude. The proportion of lower vegetation coverage showed an increased-decreased-increased trend, while that of higher vegetation coverage was on the contrary. Low vegetation coverage in area above 3880 m occupied an absolute dominant position. (4) The area weighted gravity centers of vegetation coverage at different levels were concentrated in Shawan, Shihezi, Manas and Hutubi, which showed a trend from concentration to relative dispersion.