[Objective] To analyze spatial dynamic characteristics and interrelationship between cultivated land changes and grain production in order to provide a scientific basis for improving the level of intensive utilization of cultivated land and increasing grain production.[Methods] Using land use change data obtained by remote sensing and the agricultural statistical data from local governments in 1990-2013, with the theory, technology and methods of geography and economics, we analyzed the spatial-temporal dynamic patterns of regional arable land and grain production, and developed a farmland-grain elasticity coefficient to depict the interrelationship between farmland and grain production and reveal the impact mechanism of arable land dynamic change on grain production.[Results] (1) The arable land in 1990-2000 was significantly expanded, which increased in the central and northern part in the study area while it decreased in eastern part. The grain production increased gradually. The grain production was very sensitive to the arable land changes in Siziwang Banner, and less sensitive to the arable land changes in other areas. (2) The total arable land was significantly decreased in 2000-2013, mainly occurred in central and southern area. The trend of grain production in the study area was increased after the first decrease. The food production capacity was significantly improved in the eastern and western area in the Ulanqab City and the sensitivity to arable land was low.[Conclusion] Cultivated land changes in 1990-2013 have significant effect on grain production of the Ulanqab City. The sensitivity of the grain production to the cultivated land changes has significant regional differences as well as in different periods, which was lower in 2000-2013 than that in 1990-2000.