Abstract: In drainage networks, the bottom area of the sinking inspection shaft or the horizontal flow type inspection shaft under overload condition, can provide a stagnant dead water zone for the soluble substance, which significantly changes the transporting and mixing process of the pollutants, and has a significant impact on its longitudinal dispersion.In this paper, we reviewed the related theories and model research progress on pollutants mixing and diffusion process in the dead water area of inspection shafts in drainage networks, and the research results of relevant scholars were sorted out.The influence of the dead water area of an inspection shaft on longitudinal dispersion of the pollutants was revealed.The retention effect of the dead water zone in the overload inspection shaft on the pollutants mixing and diffusion was described in detail.The ratio of depth to diameter of an inspection well was quantified, and two hydraulic thresholds were given according to different hydrological conditions.In view of the current situation that the water quality models ignore the retention effect of dead water zone, which lead to water quality prediction error, key research directions on accurate prediction models for simulating pollutants transport dispersion process in drainage network are put forward.