To evaluate the long-term effects of biochar amendment on greenhouse gas emissions(GHGs),a field experiment was conducted to examine the effects of 3-year field-aged biochar(B_3) and fresh biochar(B_0) on global warming potential(GWP) and greenhouse gas intensity(GHGI) of methane(CH_4) and nitrous oxide(N_2O) in a typical rice-wheat rotation system. Four treatments were established as control without nitrogen fertilizer(CK),urea without biochar(N), urea with fresh biochar amended in 2015(NB_0),and urea with 3-year field-aged biochar amended in 2012(NB_3). Results showed that both the NB_0 and NB_3 treatments obviously increased soil pH, soil organic carbon(SOC),total nitrogen(TN) and influenced the potential activity of functional microorganisms related to GHGs compared to the N treatment. Relative to the N treatment,the NB_3 treatment significantly improved crop yield by 14.1% while reduced the CH_4 and N_2O emissions by 9.0% and 34.0%,respectively. In addition,the NB_0 treatment significantly improved crop yield by 9.3%,while reduced the N_2O emission by 38.6% though increased the CH_4 emissions by 4.7% relative to the N treatment. Moreover,both the NB_0 and NB_3 treatments could significantly reduce both GWP and GHGI,with NB_3 being more effective in simultaneously mitigating the GHGs emissions and enhancing crop yield. Since field-aged biochar showed obvious effects on GHGs mitigation and carbon sequestration after 3 years,biochar incorporations had long-term effect on GHGs mitigation and crop production in the rice-wheat rotation system.