Energy, economy and ecological environment complement each other. The coupling and coordination development of them would provide basis for the rational use of energy, economic development, and the protection and restoration of the ecological environment. In this study, the coupling and coordination development of the Australian energy, economy, and ecological environment from 2007 to 2016 were quantitatively investigated by constructing a coupling coordination model based on coupling theory. Results showed that: (1) Australia's comprehensive evaluation index of energy, economy, and ecological environment exhibited an increasing trend. The rising trend of the energy index was obvious, the economy was relatively stable, and the comprehensive evaluation index of the ecological environment strongly fluctuated. (2) The development of energy and the economy, and that of energy and the ecological environment were gradually coordinated, and many unbalanced development patterns were found between the economy and the ecological environment. (3) Four types of coordination were observed in the three subsystems, among them, the barely coordinated categories repeated most often and the coordination degree of the three subsystems tended to grow from the global perspective. Energy, economy, and ecological environment interacted, limited, and promoted one another to form a complex system, through proper coordination, these three subsystems can jointly promote the sustainable development of society in Australia.The academic community's research on energy, the economy, and the environment has experienced the process of "single system-binary system-ternary system." Kraft and Kraft [3] first investigated the relationship between economic growth and energy consumption. Grossman and Krueger [4] observed that economic growth and environment quality exhibit an inverted U-shaped curve, which Panayotou [5] called the Environmental Kuznets Curve (EKC) relationship. These studies mainly focused on the binary systems of energy-economy, economy-environment, and environment-energy. With the increasing awareness on energy, the economy, and the ecological environment, people have realized that these binary systems are insufficient to comprehensively and systematically investigate the coordinated development of energy, the economy, and the environment. Therefore, many energy research and environmental protection institutes have cooperated with economists to construct a research framework of the three subsystems and conduct comprehensive research on their coordinated development. In 1995, Hawdon and Pearson [6] investigated the complex relationship between energy, the environment, and economic welfare by using input-output simulations. Oliveira and Antunes presented a multi objective model [7] and a multisectoral energy-economy-environment model [8] and used them to evaluate the effects of economic structure and energy system changes on the environment. Since then, the study of the relationship between the three subsystems has become a new resea...