It is of great concern for greenhouse gas (GHG) reduction of animal manure management in China due to the extreme lack of GHG emission data during animal manure composting. Therefore, the purpose of this study was to investigate the effects of turning frequency on the emission of GHG (CH_4, N_2O) and NH_3 during swine manure windrow composting through on-site observation of a full scale test in Beijing. Results showed that the turning frequency had significant impacts on the emission of both GHG and ammonia, which did not only increase the emission of GHG and ammonia, but also increased the percentage of total nitrogen loss due to NH_3 emission (42.2% at turning once a week and 70.05% at turning twice a week, respectively). Compared with N_2O emission, CH_4 emission was the main contributor to Global Warming Potentials (GWPs).