Grain production is the cornerstone of China’s food security，and the moderate fiscal support related to it can balance the effective use of public financial resources and the implementation of national security strategies.In light of the important role of rice in grain production，this paper empirically analyzes the mechanism of fiscal support on total rice production and its spatial spillover effect based on the panel provincial data of China from 2006 to 2021，using fixed-effects model，mediated-effects model and spatial Durbin model.It is found that，firstly，financial support can significantly promote the growth of rice production，though with a time lag.Secondly，the mediating effect of support is mainly realized through expanding the scale of rice production，but the effect of financial support have a negative spatial spillover， which leads to the clustering trend in the spatial distribution of rice production.Thirdly，considering the spatial heterogeneity of rice production，the yield-increasing effect of financial support is more significant in the main grain producing area from the point of view of whether it is the main grain producing area or not.Fourthly，from the level of economic development，the yield-increasing effect is more significant in the Northeast region.Therefore，it is necessary to maintain the level of fiscal support for grain production， promote a virtuous cycle of scale，efficiency，and sustainability in farming operations，prevent the negative inhibitory effects of fiscal support policies，and allocate additional funds towards major grain-producing regions，including the Northeast region.