This paper introduces the model of China's direct grain subsidy policy, adopts computable general equilibrium (CGE) theory, and advances the scheme of constructing the model of China's direct grain subsidy policy. On the basis of some assumptions, such as conforming to the complete competition of market, inexistence of move of capital and labor forces among countries, unchanged exchange rate and incomplete substitution, and the main body of behavior comprising representative households, producers, local government and central government, the model established in this paper includes production module and demand module. Moreover, the model takes into account equilibrium structure, the definition of profiting and macro condition for closure, the related coefficients this CGE model needs include Armingtion substitution elasticity of intermediate composite product, investment composite product and consumption composite product between import and domestic production; substitution elasticity among production factors; conversion elasticity of total sales between domestic absorption and export; elasticity of residents' expenditure; elasticity of price; elasticity of export demand; the relative share of ail sectors in capital stock. This paper also points out the advantages and limitations of CGE model in analyzing direct grain subsidy policy.