The minimum purchase price of rice is an important grain price support policy in China. Since the price support policy was implemented in 2004, the basic goal has been to stabilize domestic grain production and ensure food security. The key point is to clarify the effect of minimum purchase price on market price expectation. Based on provincial data for early, medium and late indica and japonica rice, we constructed a price expectation panel model to empirically investigate the impact of the minimum purchase price of rice on its market price expectations in different regions and periods. The study found that: 1) the minimum purchase price of rice contributed to positive market expectations both in the non-policy implementation area and in the non-implementation period of the policy implementation area, but its impact was weaker than the impact of the market price in the previous period in the non-implementation area, and stronger than the impact of the market price in the previous period in the implementation area. 2) During the implementation period of the policy implementation zone, the previous period of market price has a positive effect on the expected price difference （the difference between market price and minimum purchase price）, and a negative effect on the minimum purchase price. Therefore, the reform of the minimum purchase price policy should fully consider the impact of future policy changes on market expectations based on the policy goals.