To investigate the effect of biochar amendment on the global warming potential and greenhouse gas intensity in a double rice-cropping system. An inbred rice variety Zhongjiazao 17(early-rice) and a hybrid rice variety Wuyou 308 (late-rice) were selected,respectively. The present study comprised two treatments: no biochar amendment control (CK) ; and biochar amendment (B) at a rate of 20 t·hm ~(- 2),respectively. Methane (CH_4) and nitrous oxide (N_2O) emissions were measured using the static chamber-gas chromatography method during two consecutive rice-growing seasons,and analyzed the effect of biochar amendment on CH_4 and N_2O emission,global warming potential,total grain yield and greenhouse gas intensity in a double rice-cropping system. The results showed that CH_4 emissions were significantly decreased by biochar amendment in both early- and late-rice seasons,whereas no significant effect was found on N_2O emissions compared to CK. Overall,CH_4 emissions were,on average,significantly reduced by 26.9% by biochar amendment over the two-year period. In addition,the global warming potential (GWP) and yield-scaled GWP (GHGI) was significantly reduced by 26.9% and 30.3% by biochar amendment over the two-year cropping season, respectively. Biochar amendment significantly increased the concentration of soil organic matter. Biochar amendment significantly increased both early- and late-rice yield in the second year of the experiment. Therefore,biochar amendment is promising to increase rice yield and lower the global warming potential. This study provides a theoretical basis for high rice yield and reduction of carbon sequestration in the double rice-copping system.