Based on the analysis of the navigation channel situation in five rivers tail of Jiangxi province, this paper probes into the possibility of building the high-grade channel network due to the construction of the Poyang lake hydraulic engineering (PLHE). The hydro-dynamic numerical model of the river network is used to study the effect of navigation water level, navigation mileage and backwater area on different regulating water levels of the PLHE. For building the highgrade channel, the lowest regulating water level of the PLHE should be larger than 15 m.