In this study a soil polygon-based modeling method was developed by integrating DNDC with a 1:1,000,000 soil database to quantify C sequestration potential from paddy fields in Jiangsu Province under reduced tillage, no-tillage, and combined tillage (i.e., reduced tillage and increasing crop residue return to 30%). The results indicated that C sequestration potential under modeled tillage practices significantly increased compared to the conventional tillage, and was estimated to be 24.5, 47.7 and 43.8 Tg between 2009 and 2050 under reduced tillage, no-tillage, and combined tillage, respectively. The C sequestration rate under no-tillage, and combined tillage was nearly 2 times higher than under reduced tillage. In view of actual situation, the combined tillage will be one of the most realistic tillage of C sequestration for paddy fields in Jiangsu Province.