We conducted a greenhouse gas emissions study of different rice-based cropping systems in the Taihu Lake region. The results indicated that the seasonal CH_4 emission initially increased,but declined over time. CH_4 emission mainly occurred during the early stages of rice growth and decreased after the paddy soil dried. N_2O emission mainly occurred during the fertilizer application and paddy field drying stages. Compared with N_2O emission,CH_4 emission contributed significantly more to the global warming potential (GWP) during the rice season. The proportion of CH_4 emission to the total greenhouse gas emissions,which this study aimed to reduce,ranged from 94.7% -99.6%. CH_4 emissions and their GWP during the rice season varied significantly under different rotation systems,with the order of wheat-rice rotation>Chinese milk vetch-rice rotation>fallow-rice rotation,while the N_2O emissions and their GWP exhibited no significant differences. Compared with no nitrogen fertilization,applying N fertilizer significantly reduced CH_4 emission and GWP of the Chinese milk vetch-rice rotation. However,CH_4 emission and GWP did not vary with N application rates. The rice yield was largest when the N application rate was 240 kg?hm~(-2). Taking economic and environmental benefits into account,we found that a N application rate of 240 kg?hm~(-2) and a straw-return application of Chinese milk vetch not only reduced greenhouse gas emissions but also achieved the highest rice grain yield,which was recommended as a suitable cropping system for the Taihu Lake region.