The greenhouse gas (GHG) emission calculation methods recommended by Clean Development Mechanism Executive Board of United Nations Framework Convention on Climate Change (UNF-CCC) were used to compare GHG emission reduction among three livestock manure treatment processes including anaerobic/oxidation pond process, anaerobic/anoxic/oxic/membrane bioreactor (AOMBR) process and two-stage anaerobic/nitrogen-phosphorus recovery/bio-ecological process. The results indicated that when the treatment capacity of livestock manure was 69.8 t/d, the removal rates of COD by the three processes were 83.9%, 91.5% and 98.5%,respectively, and the removal rates of ammonia nitrogen by these three processes were 56.9%,88.5% and 99.4%, respectively. The values of GHG emission reduction (CO_2 equivalent) in the three processes were 9 805.3 t, 9 688.5 t and 10 491.5 t, respectively. The anaerobic units of all the three processes contributed most to the GHG emission reduction,up to 6 467.3 t CO_2 equivalent,which was enhanced by the two-stage anaerobic unit in the third process. Although the bio-ecological unit had lower contribution to GHG emission reduction, it was essential to ensure that the effluent quality could meet the discharge standards. Therefore, it is recommended that the anaerobic unit should be sufficiently utilized to recover methane,and the nitrogen-phosphorus recovery unit and bio-ecological unit should be installed to achieve excellent effluent quality and minimize GHG emission reduction in livestock manure treatment process.