As an essential influencing factor of permissible pollution bearing capacity, hydrological condition was changed significantly due to hydropower cascade development. According to the water functional division and water quality control target in Panzhihua reach of Jinsha River, the variation of dynamic permissible pollution bearing capacity (COD, NH3-N) with hydropower cascade development were calculated depending on 2-D hydrodynamic and water quality models. Furthermore, response relationship between permissible pollution bearing capacity and hydrological factors was established to evaluate the effect of hydropower cascade. The results show that the dynamic permissible pollution bearing capacity of COD and NH3-N decreased by 5.2%-27.8% and 3.8%-41.2%, respectively, and its decreased range was found to be more evident in dry season. The variation trend of permissible pollution bearing capacity and near-bank discharge was similar for different conditions. Simple coefficients between the variation of near-bank discharge and permissible pollution bearing capacity were calculated. However, a significant correlation was found with permissible pollution bearing capacity of NH3-N only.