[Objective] The impacts of sloping land conversion program (SLCP) on grain production were studied, in order to provide a scientific basis for the further development of SLCP.[Methods] This paper investigated the temporal and spatial changes of cultivated land and grain production by taking 117 counties in Shanxi Province as research units, based on the land use data and socio-economic statistics in 1990, 2000, 2005, 2010 and 2015. And the production function was used to analyze the impact of SLCP on grain production.[Results] ① The effect of SLCP to the key ecological environment control areas in Shanxi Province was remarkable. The spatial distribution of cultivated land converted to forest land and grassland was more obvious in the hilly and gully region of the Loess Plateau. ② Over the past 15 years, the total grain output and the grain yield per unit area in Shanxi Province showed an overall upward trend. The total grain output and the grain yield per unit area in key conversion counties were increased to a certain extent, and the increasing rate of grain yield per unit area was higher than the average level of the whole province. ③ SLCP showed a significant positive impact on the total grain output and the grain yield per unit area.[Conclusion] At the provincial level, SLCP will not have a negative impact on grain production. Instead, it will promote the intensive production of agriculture and other ways to improve the level of grain per unit area, and then promote the increase of grain production.