Until recently, it was commonly accepted in the scientific community that methane was produced only under anaerobic conditions through microbial metabolism. However, in 2006, Keppler et al. showed that methane can be released from plants under aerobic conditions. Subsequent experimental studies have demonstrated that aerobic methane is released from plants, and that the emission rate of aerobic methane is constant at a given temperature demonstrate biomass may be the source of plant aerobic methane. Although the exact mechanism underlying plant aerobic methane emission has not been identified to date, these experiments suggest that it is dependent on light and temperature. Over the past 20 years, atmospheric methane content has decreased due to an unknown mechanism and there seems to be an unidentified methane source, which may be related to plant aerobic methane emissions. Thus, quantitative research on methane emissions from plants under aerobic conditions and its effects on climate are critical to calculating a global methane budget. Based on a modified Keppler's model and net primary productivity (NPP) simulated by the Integrated Biosphere Simulator (IBIS), this study simulates and predicts spatial and temporal variation in methane emissions from terrestrial plants under aerobic conditions in China. It then rebuilds patterns of plant aerobic methane emission suited for China with leaf biomass, and explores the spatial and temporal characteristics of terrestrial plant aerobic methane emissions and variations in emissions among plant types. We also simulated the effect of aerobic methane emissions on climate change, especially the greenhouse effect, under different scenarios, e.g., doubled CO₂. Biomass accumulation ratios, which were used to establish quantitative relationships between NPP and biomass, and ratios of leaves and intact plant biomass were collected from previous studies. Although simulated biomass and methane emissions under the IPCC scenario A2 and B1 were generally similar between 2001 and 2012, significant differences between them emerged later in the simulation. Under the SresA2 scenario, the total annual biomass was 10803.22 Tg, leaf biomass was 1156.15Tg, and methane emissions were 2.69Tg, accounting for 7.01% of the annual national methane emissions and 29.05% of methane emissions from rice. Grassland showed the highest methane emissions under aerobic conditions, accounting for 47.53% of the annual national total emissions; mixed forests ranked the second. Forests, including coniferous forests, broadleaved forests, and mixed forests, accounted for 51.28% of the total aerobic plant methane emissions in China, while grassland accounted for 47.47%. Methane emissions were higher in south China than in the north, and higher in the east than in the west, mainly due to the different land cover and climatic conditions. Methane emissions from terrestrial plants under aerobic conditions are expected to increase in the future under both the SresA2 and the SresB1 scenarios, according to our model. The average annual growth rate of methane emissions is 9.73% under the SresA1 scenario, higher than that under the SresB1 scenario (5.17%). However, these growth rates are expected to decline under both scenarios. In the 21st century, the carbon dioxide equivalent of annual plant methane emissions will be 83.18 Tg under the SresA2 scenario, and 77.34 Tg under the SresB1 scenario, accounting for 1.39% and 1.29% of China's annual carbon dioxide emissions, respectively.