Based on the achievements of farmland grading,this paper comprehensively analyzed the change in quantity and quality of cultivated land in Yangtze River Delta. This paper has studied the impact of cultivated land change on grain productive capacity of Yangtze River Delta in the next 10 years using the research methods of quantitative analysis and comparative analysis. The results showed that: 1) The quality of cultivated land in Yangtze River Delta is relatively high and its utilization grade is above the average level in China. 2)A large number of cultivated land has been occupied by construction. According to the new round of land use general planning, the quantity and quality of cultivated land in Yangtze River Delta presented a declining trend during the next 10 years. The number of high utilization-grade cultivated land reduced more. 3) The utilization-grade of cultivated land represented the quality of cultivated land and reflected its grain productive capacity. The standard grain total yield of Yangtze River Delta was 1036.12×10⁸ kg. Standard area compared with the statistics area of grade 3 and grade 13 in Yangtze River Delta, the ratio of reduction or increase in cultivated land quantity was 0.1∶1,while the ratio of reduction or increase in standard grain total yield was 0.52∶1.The impact on grain productive capacity of high utilization-grade cultivated land change was bigger than the lower utilization-grade cultivated land. 4) Because of requisition-higher and compensation-lower in the process of cultivated land requisition-compensation balance, the grain productive capacity of cultivated land was greatly reduced. Based on what mentioned above it could be concluded that we should guarantee the double balances and protections of both quality and quantity. Improving the grain comprehensive productive capacity was the basic strategy to ensure food security.