Based on the development of hydrology science and the basic framework of physical and virtual water coupled flow theory, this study indicated that the process hydrology is an interdiscipline that can reveal the coupled flow law and associated effects of physical and virtual water in complicated system. In addition, this study makes a detailed analysis of the scientific connotation, main characteristics, framework, discipline basis, method system and core tasks of process hydrology. Given the theoretical value and practical significance of process hydrology, it can be concluded that the development of process hydrology can provide measures and new views to cope with new challenges in hydrology that the sustainable developments of nature, economy and society faces.