From the perspective of the coupling of socioeconomic and natural sciences, transitional geospace is the composite zones between natural-socioeconomic system, highlighting the particularity and complexity of the regional system of human-nature relationship. In terms of the type, the mountainous transitional geospace, which we need to focus on and deepen its understanding and cognitionis, is the key areas for the high-quality development and management of modern territorial space in China, as well as one of the important issues of the frontiers of geographical research. In the light of the elaboration of the concept, connotation and attributes of transitional geospace from the perspective of the coupling of socioeconomic and natural systems, and referring to multidisciplinary concepts, theories and methods, inspired by the principle of color gradients, this study exploratively proposes a scientific research framework for transitional geospace based on the geocoding and decoding technologies, aiming to explain the socioeconomic-natural coupling evolutionary process and its mechanisms in transitional geospace, and to provide scientific decision guidance and basis for improving the territorial space function and optimizing its development pattern in the transitional geospace. It also has application values to enrich the explorations and practices for the research of human-nature relationship and regional systems.