The Tibetan Plateau is sensitive to global climate change due to its special geographical position and unique ecological environment. In order to research the climate impacts on vegetation phenology, this paper first extracted the vegetation phenology indices using MODIS-derived normalized difference vegetation index (NDVI) data from 2000 to 2010,and then analyzed the vegetation phenology changes and their correlations with temperature and precipitation. Our study indicates that the start of growing season began in the late April, and most regions focused on May to June. The end of the growing season occurred in mid-September, and most regions focused on October. Overall, the start of growing season was relatively late in the west than in the east. The start of growing season became earlier with higher temperature in winter (from December~ February),and the winter temperature had a greater influence on start of growing season than that in spring. The increasing of summer temperature leads to the advanced recession of vegetation that caused earlier end of growing season. The increased temperature and precipitation in autumn contributed to the delayed end of growing season.