Abstract: Numerical simulation is an important method to study the pollution problem due to the wastewater discharge. Thefeatures of water flow and wastewater distribution andrelated difficulties in numerical simulation are discussed in the presentpaper. Both advantages and disadvantages of thedepth-averaged model and varied multi-layer models are analyzed when theyare applied to investigate the wastewater discharging into Three GorgesReservoir (TGR). The present study may be helpful to the furtherdevelopment of wastewater effluent model for TGR as well.