A numerical model for simulating N2O emissions in agroecosystem was established. Validation of the model with the observed data showed that the model simulated the process of N2O emissions in fields fairly well. The numerical analysis showed that the N2O emissions were interrelated well with average temperature during rice growth periods. Analysis of N2O emissions and meteorological factors by using power spectrum found that the change of N2O emissions had 7-9 year cycles. Sensitivity test showed that the N2O emission increased with temperature enhancement.