Urban expansion reflecting human activities and climate change are the two main driving forces of global and regional ecological environmental change. As an important indicator of characterizing vegetation ecology in global land surface,vegetation NDVI provides a probability to study the impact of urban expansion and climate change on regional ecological environmental change. Compared with the previous independent analysis of the impact of urban expansion or climate change on vegetation NDVI,this paper will analyze the impact of urban expansion and climate change on vegetation NDVI together,and also analyze the difference of the two driving forces,which may provide a probability to quantitatively distinguish the effects of climate change and human activities. Taking Xian City and its nearby area for example,the impact of urban expansion and climate change on vegetation NDVI was analyzed based on the land use data,MODIS NDVI,yearly temperature and precipitation data in 12 meteorological stations,and the methods including linear trend analysis,correlation coefficient,partial correlation coefficient and t-test. Results show as follows:(1)The process of vegetation NDVI change was divided into 2 stages,2000-2007 and 2007-2014. The former stage showed significant linear increasing trend,which was mainly distributed in Loess Plateau area in northern study area and northern Qinling in southern study area. The latter stage showed significant linear decreasing trend,which was mainly distributed in Guanzhong plain,especially in Xian City and its nearby area.(2)Urban area had increased 1 428.27 km~2,which was mainly from 2010 to 2015 in the study area. Vegetation NDVI in the area of urban expansion showed a significant linear decreasing trend(P<0.05).(3)Overall,the correlation between vegetation NDVI and precipitation was higher than that between vegetation NDVI and temperature. At the same time,negative correlation between vegetation NDVI and temperature,precipitation was distributed in Xian City and its nearby area,which indicated that the impact of urban expansion was higher than that of climate change on vegetation NDVI. The conclusions are that vegetation NDVI was controlled by climate change overall,but was influenced by urban expansion more seriously in local area; the response of vegetation NDVI to climate change fluctuated,and the vegetation NDVI showed linear decreasing trend to urban expansion. The conclusion of this research may have some limitations and needs to further study the relationship between vegetation NDVI and climate change,human activities at large scale and using long time-series data,to obtain a general conclusion.