Abstract: In the process of urbanization, the planning and construction of urban green space has been continuously improved, and a green space ecosystem with urban characteristics has gradually formed. The urban green space ecosystem has the ecological functions of beautifying the environment, purifying the air and reducing noise of the area and has played an important role in urban regeneration and human health. The ecological and hydrological processes of urban green space are important factors in studying the functions of urban green space ecosystems. Especially, evapotranspiration, as an important link in the interaction between the ecological process and the hydrological process, has great significance in the research on urban green space ecological hydrology. The progress and directions in domestic and foreign research on urban green space ecosystem are summarized from the three aspects of content, scale and method. It is proposed that in the study of urban green space ecosystem ecohydrology, the pro- blem of scale conversion should be considered one of the main issues in the study of evapotranspiration of urban green space ecosystem. Meanwhile, the hydrological process and the ecological process of the urban green space ecosystem should be integrated in terms of space and time, and the mechanism of the interaction among the factors affecting the evapotranspiration of the green space ecosystem is one of the urgent scientific problems to be solved in the research on urban ecological hydrology. Finally, in the future, importance needs to be attached to the research on the mechanism of the interaction between evapotranspiration of urban green space ecosystem and urban rainstorm waterlogging, on the long-term positioning observation of hydrological process of urban green space ecosystem at different scales, and on the impact of green space layout on human health.