Metabolic theory shows the link between size of individual organisms, and the stoichiometric dependence of the metabolic rate of organisms on temperature by using first principles derived from physics, chemistry, and biology. Based on the further development of metabolic theory, the effects of temperature on quantitative relationships between the exchange of matter and energy, or the rate of those, and size of organisms can be predicted. Many ecological structure and phenomena may be explained by metabolic theory. Therefore, macroscopic ecological processes and microcosmic biology are directly integrated by the regulating theory of metabolism. The paper has summarized recent developments in metabolic ecology which take macroscopic ecological process and the quantitative law of the size dependence of metabolism as their focus. We explicitly present the rule that the rate of ecological processes (or metabolism) depend on resources, stand biomass (i.e. size of the ‘reactor’), the molecular system and their interaction. And we have developed a cubic sketch model of the coupling relationship between the efficiency of plant use of resources, and light, water and chemical elements. We predict that the development of metabolic ecology as the meeting point of macroscopic ecological processes and microcosmic biology will drive integration and further advances in the life sciences.