As a practice of exploring harmonious coexistence between man and nature, harmonious progress of society, and steady economic development, eco-city is an important measure to achieve sustainable development. As the core of geography research, man-land relationship is an important issue that must be faced and discussed in social development. This study discusses the concept and framework, process and mechanism, the evolution of theories and methods of eco-city and man-land relationship research, and identifies their differences. Eco-city planning, being highly comprehensive, plays a key role in optimizing resource allocation, adjusting the spatial layout, coordinating various undertakings, and improving urban functions. It shifts its focus from the speed and scale of urban growth to urban growth capacity, ecological carrying capacity, and quality of life. The study of man-land relationship aims to explore the interaction of various elements of man-land system and the overall behavior and regulation mechanism. The major themes vary with the evolution of man-land system, and the accurate analysis of man-land relationship faces a series of challenges in theory, technology, and data. Man-land relationship can be applied as a broader system framework for eco-city study, and the methods of eco-city can be used as specific tools for studying man-land relationship. Our study also points out that the complex system science and comprehensive integration method are the key research directions of eco-city and man-land relationship. The integration of research on eco-city and man-land relationship can better solve complex problems and move towards a common goal-sustainable development.