During the working process of a trailing suction hopper dredger,the height of sand bed and the soil type as the main bases to adjust the dredging operator’s strategy,cannot be directly measured by sensors currently available onboard.Considering the sedimentation model of a hopper,we simulate the changes of soil type by two scenarios while dredging after analyzing the sand bed and soil grain diameter,the most important soil-dependent parameter.We take Xinhaifeng dredger’s construction data as an example to calibrate the model used in practical.The pattern search calculates the average soil grain diameter of one working condition offline.We use particle filter algorithm to estimate the sand bed height and soil grain diameter online on the basis of verifying the dynamical sedimentation model.The simulation results show that the model of the grain diameter as a random walk contributes to a better performanc of fitting the logistic curve of the total loading mass.On the other hand,the sand bed height has a relationship with the situ soil excavated.The results provide a reference for dredging engineering,which can be applied in the decision-support systems of the hopper dredger.