Abstract: As an ecological barrier for preventing the invasion of wind-blown sand and a major water source in Beijing,the Bashang region in Tianjin and Hebei Province is significant for constructing the ecological security in capital economic circle and for achieving the coordinated development of the economy,society and environment. In this study,the MODIS NDVI remote sensing data were analyzed,and the spatiotemporal change of vegetation coverage in the Bashang region during the period of 2005-2015 was identified. The analysis methods used in the study included the linear regression,coefficient of variation,R/S analysis and other mathematical methods. The results are as follows:① The regional difference of vegetation coverage was obvious in the Bashang region over the past 11 years,and the vegetation coverage increased from the west to the east;② Area of the regions with the very significant improvement and significant improvement of vegetation coverage was the largest and occupied 65.89% of the total study area. Areas of the regions with insignificant improvement of vegetation coverage and with vegetation degeneration occupied 32.28% and 1.82% respectively; ③ The holistic stability of vegetation coverage was high in the east but low in the west. The area of the regions with high stability and relatively high stability of vegetation coverage was the largest and occupied 61.32%. The areas of the regions with medium stability and relatively low stability of vegetation coverage occupied 24.35% and 14.33% respectively; ④ In the future,the areas of the regions with continuous improvement of vegetation coverage,potential vegetation degeneration,continuous vegetation degernation and potential improvement of vegetation coverage would occupy 59.48%,38.67%,1.04% and 0.82% respectively.

Key words: vegetation coverage, spatiotemporal analysis, MODIS NDVI, change trend, risk assessment, Bashang region, Hebei Province