China has conducted major changes to its main grain policy instruments concerning rice, wheat, soybean and maize since 2014 to combate challenges such as apparent over-supply of these products at higher-than-world market prices, rapidly acccumulations of government stock, and mounting pressure to increase imports. These reforms include overhauls of stockpiling policies for soybean and maize, stabilization and reductions of minimum support prices for wheat and rice, and consolidations of various domestic support programs. Such policy changes have been thoroughly characterized in the OECD’s PSE estimates. This paper reports recent modeling efforts in understanding these policies changes by extending the OECD’s PEM partial equilibrium model to cover China. This extension offers a first direct application of the new PSE estimates on China’s recent policy changes in the PEM framework. Domestic and international market impacts as well as welfare effects of such reforms are evaluated through a series of simulations of the PEM model. To reveal the strengthes and weaknesses of the PEM approach, similar experiments are also conducted using the GTAP model framework. A comparison of the results of the two modeling approaches also offers a more balanced picture on the impacts of these reforms.