Vegetation, the main component of terrestrial ecosystems, is not only a sensitive indicator of global climate change, but also regulates the climate through energy, water, and carbon exchange between the terrestrial environment and the atmosphere. Understanding the mechanisms of growth responses of vegetation to climate change is of great significance for projecting future vegetation change and its implications. Using the satellite-derived normalized difference vegetation index (NDVI) and climate data of the period between 1982 and 2012, we investigated changes in the growing season NDVI and its response to climate change in China based on trend analysis, piecewise regression model, and correlation analysis. Our results indicate that (1) In the past thirty years, the NDVI of the study area increased, with the linear tendency being 0.2%/10a. There exists two distinct periods with different increasing trends, with the linear tendency being 1.2%/10a and 0.6%/10a during 1982-1997 and 1997-2012, respectively, the two periods of which all through the inspection by a significant level of 0.05. (2) In spatial, the areas with increased vegetation NDVI are mainly distributed in the Loess Plateau of Shanxi, the middle and western regions of Xizang, and the Junggar basin, whereas the regions with decreased vegetation NDVI are mainly distributed in the Da Hinggan Mountain, Xiao Hinggan Mountain, and Changbai Mountain in the northeast of China, the Altai mountain and the Tianshan Mountain in the north of Xinjiang Province, the Yellow River source region, and the Qinba Mountain, of which, the magnitude of decrease in the northeast of China, the Tianshan Mountain, the Altai Mountains is particularly remarkable. This phenomenon indicates that vegetation activities in mid-and high latitude mountain regions declined. (3) Spatial differences occur in response to temperature and precipitation from vegetation in different regions. Longer response duration of vegetation to temperature was detected in the north of China, whereas vegetation in the south of China showed not more than one month time lag. In contrast, vegetation in the north of China showed not more than one month time lag, but in the south of China, except for Yunnan Province, more than one month time lag was observed, and the correlation increased with the extension of time lag. (4) The increased vegetation coverage is mainly attributed to climate change and the implementation of the ecological protection project, the latter especially strengthened the impact of human activities on the vegetation increase after 1999. Of which, the decrease in vegetation in the northeast of China, the Tianshan Mountain, and the Altai Mountains can be attributed to the decline in precipitation, whereas the deterioration in the southeast of China may be more related to urbanization. Over the last decade, the project on the conversion of degraded farm land into forests and grass land in China has achieved encouraging results. However, the most drastic climate change also occurred during the same period. Although climate change probably played a key role in the trends of vegetation growth on a long time scale, human activities are also an important factor driving vegetation change. However, the exact influences of climate change and human activities on vegetation growth remain unclear; further studies are necessary to obtain accurate conclusions.