Abstract: Under the background of firmly ensuring the grain security and maintaining the ecological security, the application effect of direct subsidy policy for grain production in the Inner Mongolia Autonomous Region was analyzed in order to provide policy suggestions for promoting the grain yield increase in a safe and ecological way. By using the panel data vector auto regression model and taking the macro data of 12 League cities in the Inner Mongolia Autonomous Region from 2004 to 2018 as the research sample, Granger causality test, impulse function analysis and variance decomposition on the direct subsidy policy of grain production in Inner Mongolia were conducted in this paper. The results showed that the policy did not significantly promote the grain yield and ecological security. Therefore, it was suggested that we should explore the method of subsidies according to the output of commercial grain, guide different regions to appropriately arrange the scale of grain production according to the carrying capacity of water resources and cultivated land, and improve the matching degree between resource ecology and grain production.