This paper determines the function values of Yongtai county ecological system in Dazhangxi river basin in water supply, electrical supply, production, tourism, atmosphere conditioning, water reserve and flood prevention, pollution reduction and biological habitat, and uses market values, travel expense, alternative market values and shade engineering to evaluate its service function values. Its gross service values reach 14.987 billion RMB of Yongtai county ecological system in 2017, of which production contributes the most, up to 7.278 billion, the core function, then followed by pollution reduction, water reserve and flood prevention, atmosphere conditioning, biological habitat, tourism, electrical supply and water supply, in a descending order, showing the contribution of Dazhangxi. This paper presents suggestions on developing river basin ecological tourism, improving electrical and water supply function values based on Dazhangxi's situation and features.