Ecological Function Regionalization (EFR) is viewed as one of the most important strategies to support ecosystem management and sustainable development worldwide. EFR is a systematic method for classifying and mapping ecological unit at the regional scale, based on integrating the information of the nature and distribution of ecosystems, as well as ecological patterns and processes and the interrelationships among social, physical, and biological systems. Depending on different temporal and spatial scales, ecological units are designed to exhibit similar patterns in many characteristics associated with landscape heterogeneity. This paper presents a comprehensive review of EFR theories, describes the EFR definitions and concepts, examines the underlying principles for EFR, and shows how the framework for ecological unit designing can be used in resource planning and management. This study is aimed to provide a systematic method for ecological unit recognizing and mapping, considering how we understand the spatial distribution of ecosystems and how to achieve regional sustainability and ecosystem health. The driving factors were then recognized to better measure the effects to the ecological pattern and process at different temporal and spatial scales. Finally, we propose a classification framework for EFR to benefit decision making on regional ecosystem management.