Characteristics of spatial distribution and temporal variation of aerosol optical depth (AOD, on 550nm) in 2000~2014 in Mainland China were analysed in this paper with monthly, seasonally and yearly mean data, derived from the NASA MODIS04_L2 product. Specifically, we used spearman-test method to investigate the seasonally and yearly variation trends of AOD over China from 2000~2014. The results were as follows:all-year high value of AOD occurred in the Sichuan basin, the southern Sinkiang basin, the central China region, the Yangtze river delta, the north China plain, the Guanzhong plain and the Pearl River delta; while all-year low value of AOD, in the western Sichuan, the southeast Tibet, the border of Inner Mongolia and northern Hebei Province, and part of the Hetao area, occurred. The value of AOD in Northwest China showed a decreasing trend, of which the junction of western Sichuan and southeast Tibet and Shaanxi-Gansu-Ningxia showed a significant downward trend. The AOD value in the eastern part of China mainly showed an upward trend, and there was a marked upward trend in central China, the Yangtze River Delta, the North China Plain and the Guanzhong Plain. AOD value changes more significantly with the seasons, the specific performance is higher in spring and summer, autumn and winter lower. The high value area of AOD and the area of upward trend are basically located in the southeast of Heihe-Tengchong Line, indicating that human activities have a significant impact on the AOD value.