Abstract: The deterioration of river ecosystems has attracted worldwide attention in recent decades, and the urban river revitalization campaign has been launched since the 1990s. Successful river ecological restoration is inseparable from the restoration of landscape hydrology at the watershed scale. Applying the concept of “functional flows” to restore the essential ecological processes may be the best option under the current challenging urban situations of China. In view of the lack of research and practice to restore the overall structure and function of river ecosystems in China, this study analyzed three planning and research projects of almost entirely channelized Los Angeles River in California, USA, during the past two decades. In this process, we focused on the stream ecosystem restoration, hydrological restoration in particular, including flood protection, establishment of regional ecosystem, specific ecological restoration measures, and long-term ecological flow study. We concluded with implications in following three aspects: the planning scale, technical support, and collaborative mechanism for urban river restoration in China, especially for the arid northern region.