Abstract: Study of the grassland productivity and its response to the climate change has been an important aspect of the global change research.By using the ArcGIS interpolation technique,the observed data from 32 meteorological stations in the Mongolian Plateau are interpolated into the 1°×1° grid data,and then the spatiotemporal distribution characteristics of the above ground net primary productivity (ANPP) of the vegetation over the Mongolian Plateau from 1961 to 2016 are simulated by the CENTURY model.The results are shown as follows:(1) The spatial and temporal distribution of the ANPP simulated by the CENTURY model can well reflect the change of the grassland productivity in the Mongolian prairie,and the distribution of the ANPP in grasslands changed from north to south gradually from east to west.(2) The yields of meadow steppe and typical steppe are decreasing over time and the decrease rate of meadow steppe is higher,and the yields of desert steppe is rising over time.The largest total yields are in the typical steppe,and the lowest total yields are in the desert steppe which has the largest area.(3)The precipitation is the key factor for the grassland productivity.In the wetperiod,there exists the transformation of desert steppe→typical steppe→meadow steppe,while the process of dryperiod conversion is the opposite.The total yields of Mongolian steppe have the largest decrease when it is changed from the warmwet period to the drycold period. In contrast,the total yields have the largest increase when it changed from drycold to warmwet.

Key words: spatiotemporal distribution, ANPP, CENTURY model, Mongolian Plateau grassland