Abstract: Understanding the coupling law between cropland use and grain production is the basis for food security and sustainable development. Based on model simulation, GIS, multi-objective scenario simulation and quantitative analysis on the response of grain production to cropland use changes,this study explored the key driving factors of grain production changes and potential of grain production.The study can provide a reference for decision-making on the dynamic control of cropland use and food security in Taihu Lake Basin.The results are as follows:(1) Spatial aggregation of cropland use and grain production changes was significant.The changing rate of cropland quantity and quality(CQQ) , cropland structure,and cropland pattern were 39.2%,23.6% and 19.3% respectively from 1985 to 2015. Affected by cropland changes, changing rate of grain production was 44.1%.(2)The contribution of CQQ changes to decline in grain production was 50.7% from 1985 to 2015,and the contribution of cropland structure and CQQ changes to decline in grain production were 43.4% and 76.3 % respectively in the first 15 years and next 15 years. The CQQ changes were the main factor that affected grain production in counties accounting for 56.8% which located in the north of Taihu Lake Basin. Cropland structure change were the main factor that affected grain production in counties accounting for 24.3% which located in the southeast of Taihu Lake Basin, and counties accounting for 18.9% which were along Hangzhou-Tongxiang-Jiashan were mainly effected by cropland structure changes.With the evolution of time, the decline in grain production and influence degree of CQQ changes on grain production increased significantly. (3)Cropland decrease and food security pressure will continue in the future.With the changes of scenarios from trend growth to cropland protection, the counties whose grain production are mainly effected by CQQ changes reduce by 53.5%, the counties whose grain production are mainly effected by cropland structure and cropland pattern increase by two times and 1.25 times respectively,and regions with grain increase grow from 5.4% to 54.1%.It is concluded that the response patterns are different in different region and the sensitive counties of grain production change to scenario changes will become the main potential area of grain recovery and cropland adjustment in the future.