Ecological stoichiometry is the study of mass balance of multiple chemical elements in ecological ecosystems; it analyzes the constraints and consequences of these mass balances during ecosystem processes such as competition, predation, parasitism, and mutualisms, based on general laws of physics, chemistry, and biology. At present, C∶N∶P stoichiometry has been incorporated successfully into many levels of biology from molecular, cellular, individuals, population and communities to ecosystem and globe. Thus, ecologists have become aware that stoichiometry could provide a new tool to study ecology in most ecosystems. Along with this trend, C∶N∶P stoichiometry is actively used in ecological interactions since C, N and P are the three most important elements during ecological interactions. This article reviews the application of C∶N∶P stoichiometry to the studies of ecological problems at different levels, including species, community and ecosystem. Meanwhile, we also put forward some perspectives for future research to be conducted with an aim to promote this discipline of research in the world.