Digital River Basin, as an information infrastructure for the watershed science, is a research environment that supports advanced data acquisition, storage, management, integration and visualization as well as other computing and information processing services over the Internet in the river basin scale. The “Digital Heihe River Basin” can be considered as an implementation of the Digital Earth concept in the Heihe River Basin, the second largest inland river basin of China. The Digital Heihe River Basin is composed of an information cyberinfrastructure and its applications. The former is further built up by a data integration platform, a modeling system and an automatic observing system, and the latter are various applications using integrated models and decision support systems. The first paper of these series papers provides an overview on the Digital Heihe River Basin. The data acquisition and integration of the Heihe River Basin have been partially completed; more than 1000 GB science data are available on the Internet with “full and open” data sharing policy, which supports various kinds of research work in the river basin successfully. A primary integrated model and a spatially explicit decision support system have been developed. For the next step, the data integration, modeling, automatic observing, information distribution, high performance computing, and scientific computing visualization are proposed to be integrated as a system of systems in the framework of e-science, to support the watershed science studies in the Heihe River Basin.