In order to accurately evaluate the storage capacity of reclaimed land and reasonably select treatment technologies for dredged slurries, based on the theory of sediment transportation mechanics, dredged slurries are divided into three particle-size fractions: d<0.005mm, 0.005mm≤d≤0.01 mm, andd>0.01mm. The variation of relative content for each particle-size fraction was analyzed, and it was determined that the main reason for grain sorting of dredged slurries is the relative movement of particle-size fractions d>0.01mm and 0.005 mm≤d≤0.01mm. Using the sorting coefficient to quantify the significant degree of grain sorting of dredged slurries and the deviation coefficient to quantify the influence of grain composition of in situ mud on grain sorting, the relationships between the sorting coefficient and deviation coefficient and soil properties in reclaimed land were analyzed, and a preliminary quantitative method for grain sorting of dredged slurries in reclaimed land is proposed. The results show that the sorting coefficient decreases with the increase of the distance from the filling inlet and shows a power function distribution, and the significance of grain sorting decreases longitudinally. The sorting coefficient is at its maximum near the filling inlet, where grain sorting is remarkable and the particle-size difference is large. However, it is small near the water outlet, where grain sorting is unremarkable and particle-size distribution is uniform. The deviation coefficient decreases first and then increases longitudinally in reclaimed land, and shows a spoon-type distribution, showing that the soil properties in the forepart and posterior segment of reclaimed land are significantly different from those of in situ mud, but the soil properties in the middle segment of reclaimed land are similar to those of in situ mud. The longitudinal distributions of the sorting coefficient and deviation coefficient are strongly correlated with zoning of soil properties in reclaimed land.