Large-scale terrestrial ecosystem science research becomes an important research field with the promotion of meeting the scientific demand of biodiversity conservation, global climate change mitigation, regional eco-environment governance, and social sustainable development. It is developing rapidly under the guidance of China's ecological civilization construction strategy. Here, we systematically discussed the missions, theoretical foundation and methodology of large-scale terrestrial ecosystem science research and proposed a new theoretical foundation, conceptual system and logical framework for macroecosystem science research on the basis of macrosystem ecology theory. It elaborated the discipline connotation and application of the macroecosystem science to 1) deve-lop the conceptual network of ecosystem science based on the systematic characteristics of ecosystems; 2) develop the theoretical system of ecosystem state change analysis based on the ecosystem integrity and emergence characteristics; 3) develop the theoretical system of integrated research for ecosystem structure-process-function-service cascade relationship based on the attributes and state of ecosystems. We also discussed the methodology and technical system of regional and continental macroecosystem science research, and highlighted the urgency to construct a new generation of continental ecosystem observation and research network, and to develop the network observation-network experiment-numerical simulation-knowledge fusion four-in-one infrastructures.