The pioneering work by Keppler’s group on large aerobic methane production from plants (AMP) made it an urgent requirement to re-evaluate atmospheric methane sinks and sources and its global budget. However, there is still considerable controversy on the existence of AMP, the underlying mechanisms and its emission rate. Recent researches demonstrated that a fraction of methane emitted from plants is actually produced by methanogenic archaea in soil or/and in the anaerobic tissues of roots and trunks of woody plants. Plants transport methane to the atmosphere by molecular diffusion and pressure-difference-driven convective flow. There are also evidences that methane produced in plants is probably through reactive oxygen species (ROS), which generates methane from methoxyl groups in pectin, lignin and other cell wall constituents. Since ROS production is stimulated by environmental stresses, higher AMP was expected and has been observed under high temperature, intense light, UV radiation and other stress conditions. The estimated emission rate of phytogenic methane, either by extrapolation from leaf level measurement or by nverse analysis based on atmospheric methane concentration and carbon isotope composition monitoring, varies largely in different biomes at regional and global scales. Further field studies covering more species and communities are needed toimprove the estimation of aerobic methane emission rate and evaluation of global CH4 budget, as well as to deepen our understanding of AMP mechanisms.