In this paper, DEA-Malmquist model is used to measure the corn production efficiency of 17 main production areas in China from 2005 to 2017, and Tobit model is used to study the impact of temporary storage system reform on corn productivity. The results show that the overall corn productivity in China is high, showing an inverted "N" trend. The increase of TFP before 2015 is the result of technological progress, and the decrease after 2015 is the result of scale effect. The overall trend is North China＞Northwest＞Northeast＞the whole country＞East China＞Southwest, but the regional productivity changes in different periods are quite different, and the northeast region is the main driving force for this change. Maintaining market stability, reducing land cost and increasing machinery cost have promoting effect on productivity. From the actual effect of the temporary storage system reform: the reform of temporary storage system promoted the increase of corn productivity in the main producing areas of China, but did not cause a big market shock. Finally, some suggestions were put forward to ensure the stability of the corn policy reform, the transparency of the market, and timely adjust the transformation and upgrading of the agricultural mechanization industry in the main corn producing areas.