The grain circulation system as well as the purchase and storage system，which are based on the minimum purchase price of rice and wheat and the temporary storage purchasing price of corn，are to be reformed. But the reform is facing new contradictions and challenges. Market-oriented grain pricing mechanism reform and destocking of policy stock are against the benefits of state-owned grain enterprises；thus the reform will certainly affect the current interest structure. Deepening the reform of state-owned grain enterprises shall detach the function of purchase and sale of policy stock from the China Grain Reserves Corporation. The rule of setting price covering full cost during the sale of policy stock has been loosened. But the auction reserve price should be compatible with the market. Meanwhile，efforts should be made to improve the companies’ ability to purchase grains through the innovation of loan policies.