The Coordinated Large-Scale Environmental Observatories (CLEOs) was a national monitoring network plan based on the field observation, focusing on the integration of discipline at basin scale and finding solutions for the water problems. The paper comprehensively introduced the plan of the background, general charts, focuses and operation stages of the plan. With a view to the research situation of hydrology and water resources in our country, Pointed out the possibility of establishing a large-scale observation network in the northwest inland river basin in China is pointed out.