Achieving the goal of zero hunger within the goal of sustainable development requires improving the resilience of food systems to various types of risk shocks; food systems have shown significant vulnerability to COVID-19 outbreaks and transmission. By analyzing the impact of China’s lockdown policy and food security emergency policy in 2020 on food prices during the COVID-19 pandemic, we can clarify the role of policy intervention in enhancing the resilience of the food system, which can provide guidance, using China’s experience, for dealing with global food safety emergencies in the future. Firstly, we selected Beijing, Shanghai and Guangdong as food-consuming areas, and Shandong, Henan, and Hubei as food-producing areas. We also collected food security emergency policy data from the Chinese government website during the COVID-19 pandemic. Secondly, a difference-in-difference method was used to observe that Chinese cabbage and pork prices in the main food-producing areas and food-consuming areas rose more obviously after the adoption of lockdown policy, and Chinese cabbage and pork prices in the food-consuming areas increased more obviously than those in food-producing areas. However, staple food prices have not risen significantly. Thirdly, the response of four kinds of food prices to the food security emergency policy is analyzed quantitatively and graphically using the food price volatility index and food price increase rate; we observed that the response of food prices to the food security emergency policy is related to the food types and regions. For food types, the fluctuation degree and increase in Chinese cabbage and pork prices decreased significantly after the adoption of the food security emergency policy. For regions, when the food security emergency policy was adopted, the food prices in the main food-consuming areas fluctuated more obviously than those in food-producing areas. Finally, we found that the implementation of the transport policy and the joint supply emergency policy in the main producing and consuming areas has played a very significant and positive role in stabilizing food prices.