Fractional Vegetation Cover （FVC） is an important parameter to describe the change of land surface vegetation. It plays an important role in surface process simulation， climate modeling and global change research. It is of great significance to study the change of vegetation coverage. Based on the reconstruction of MOD13Q1 NDVI data from 2005 to 2020， the temporal and spatial variation characteristics of vegetation cover in Tianshui City were studied and analyzed by using dimidiate pixel model and maximum value composite method. The results show that the vegetation coverage of Tianshui city shows an increasing trend from 2005 to 2020. The increasing areas mainly include the two sides of Xihe River， the middle， East and northeast of Tianshui city； The low vegetation coverage of the whole city has shifted to medium and low vegetation coverage and medium vegetation coverage. The vegetation coverage on both sides of the Xihe River Basin has increased significantly， especially in the north of the Xihe River； The vegetation coverage in the west of Qinzhou District， the middle and west of Gangu County and the west of Wushan County showed an increasing trend， and the ecological environment improved significantly； The change of high vegetation coverage area is small and basically remains stable. The results reasonably explain the spatial change of vegetation cover in Tianshui City， which can provide an important theoretical basis for ecosystem protection and environmental governance.