Rapid urban development promotes economic development and leads to resource and energy shortage, ecological degradation, environmental pollution, traffic congestion, and other problems. Greening and ecologization have become the trend of urban development. Green ecocity is an ideal model of the livable human city in which people and the environment coexist harmoniously and develop sustainably. The ecology is the primary theoretical basis of a green eco-city, which is positively influenced by the 5R principles. In the present manuscript, we summarised the content and development of the 5R principles and provided some applications of the 5R principles in constructing some ecocities in various countries from the economy, environment, and society angles. Besides, we discussed the associations of the 5R principles with the spiritual world. It will offer the fundamental theories of the 5R principles for constructing and developing a green eco-city. Although applying the 5R principles in green eco-city construction is still in the practical stage, it has already triggered a multi-faceted reflection on the issue. The 5R principles influence urban development projects worldwide, promoting economic, social, and environmental sustainability, thus leading to a healthier and happier life for people.