Abstract: In order to find out the influencing factors of grain production fluctuation in Jiangsu Province, and to speed up the structural reform of grain supply side, the grain production of Jiangsu Province from 1999 to 2015 was divided into two periods according to the characteristics of grain yield in Jiangsu Province. The dynamic analysis of 10 influencing factors in these two periods was performed using the method of gray correlation analysis. The results revealed that grain planting area was the most important factor affecting the grain yield in Jiangsu Province. The effective irrigated area and total power of agricultural machinery had experienced the change from weak to strong. The agricultural expenditure ratio was important, although its pulling effect was weakened. A large number of chemical fertilizers and pesticides have a great effect on the grain yield, and there is a big increase in utilization rate. On the macro level, the impact of science and technology on grain production is increasing, followed by policy and natural factors. In order to increase the grain output of Jiangsu Province，it is suggested that more efforts should be put to stabilize the planting area of grain crops，improve the level of agricultural science and technology, actively develop green food production, and increase the financial input to agriculture.