The 19th National Congress of the Communist Party of China called for accelerating the grain purchasing and storage system reform to ensure national food security. The 20th National Congress of the Communist Party of China further emphasized the foundation of food security should be strengthened in all aspects to maintain the self-reliance in food supply. Whether the market-oriented reform of purchasing and storage system can stimulate the role of market mechanisms and improve the efficiency of grain production has an essential influence on stabilizing the domestic grain supply and ensuring national food security. Therefore，this paper uses the panel data of 247 cities in major corn-producing areas from 2011 to 2020，constructs DID model and intermediary effect model and analyzes the impact of the reform of the acquisition and storage system on the total factor productivity of corn. The results show that：1）The reform of purchasing and storage system has a positive impact on corn TFP in Northeast China，but with the deepening of the reform， the growth rate of TFP fluctuates. 2）Further research demonstrates that there are significant regional differences in the impact of the system reform of purchasing and storage. The reform has apparent positive effects on Inner Mongolia and Heilongjiang province，especially on the first，fourth and fifth accumulated temperature zones，while the impact on Jilin and Liaoning provinces is not obvious. 3）The reform of purchasing and storage system affects corn TFP through alleviation of market distortion and the aggravation of market risk. The alleviation of market distortion helps to improve TFP，while the aggravation of market risk reduces the growth of corn TFP. The government should pay attention to the TFP of corn after reform，give full play to the market function， and implement supporting mechanisms to reduce risks and stabilize fluctuations to ensure the high-quality development of maize production and safeguard national food security.