The river networks of the Xiaoshaoning Plain have an insufficient water supply and poor water fluidity. To solve these problems, a pattern for water diversion and allocation in the Xiaoshaoning Plain was developed, and the effect of the Eastern Zhejiang Water Diversion Project on the improvement of the water environment in the plain river network was analyzed, based on the Eastern Zhejiang Water Diversion Project and the diversion and drainage projects of the region. This research provides technical support for the treatment of wastewater, according to the co-governance mode for five water categories for the plain.