In this study, we used life cycle inventory(LCI)to analyze the energy consumption and greenhouse gas emissions of wheat-rice rotation system with straw returning at each phase of the life cycle. Global warming potential(GWP)of this system was also evaluated. The life cycle of the wheat-rice rotation system was divided into three phasesraw material mining, agricultural supply production and crop growing. Three straw returning rates were designed:chemical fertilizer only(N1), chemical fertilizer plus whole rice straw returning(N1+S), and chemical fertilizer plus half rice straw returning(N1+0.5S). We found that agricultural supply production(nitrogen fertilizer production) and raw material mining accounted for nearly 70% of energy consumption of the whole life cycle, while cropland was the main source of GHG emissions. In N1+S and N1+0.5S treatments, crop yields increased by 14.31% and 15.46%, while CO_2 emission per tonne of yields decreased by 27.05% and 31.23%, and N_2O emission by 17.74% and 14.51%, but CH_4 emissions increased by 39.56% and 12.38%, respectively, compared with no straw returning. However, straw returning significantly decreased GWP on 20- and 100- year time scales. Our findings indicate that applications of straw and nitrogen fertilizer could help to reduce energy consumption and GWP in wheat-rice systems.