[Objective] Determing the optimal amount of N-fertilizer inputs for rice production is significant to improve the agricultural management in the coastal saline reclamation area, Eastern China.[Methods] Combining denitrification decomposition model(DNDC) and dichotomy method, this study simulated rice yield dynamics during the whole life cycle under six fertilization situations (10%, 20%, 30%, -10%, -20% and -30% of additional N-fertilizer inputs). And the optimal interval of N-fertilizer inputs and corresponding ecological impacts were explored.[Results] ① The rice yield in the study area was 6 431.67, 5 939.22, 5 439.66, 7 686.51, 7 739.94 and 7 739.94 kg/hm² 10%, 20%, 30%, -10%, -20% and -30% N-fertilizer inputs, respectively. ② The optimal interval of fertilization was from 10% to 20% of additional fertilizer inputs, namely, 519.0~566.18 kg/hm² of N-fertilizer inputs. And the optimal N-fertilizer inputs was 528.214 kg/hm², according to dichotomy analysis. ③ Based on the optimal amount of N-fertilizer inputs, the nitrogen oxide emission was 9.24 kg/hm² during full rice growth period, which showed a good environmental benefit.[Conclusion] The optimal amount of N-fertilizer inputs during rice production in the study area is 528.214 kg/hm². This optimal N-fertilizer inputs, can improve the rice yields of saline soil to the top level and produce a better environmental benefit.