The paper introduced the basic conditions and calculation methods of ecological water requirement of Tuoshi station, the immigration control section. Based on Tashi station water series interpolation precision analysis, it select Tashi station and Linjiacun station water year-round monthly extended access toTuoshi station monthly water from 1991 to 2002, with the lining data from 2003 to 2007 composition of ecological water demand calculation in water series. Finally, it calculated and determined the Tashi station ecological water demand witch was 1.35 billion cubic meter, then, suggest that we should strengthen construction of Tuoshi hydrological station in the future.