Abstract: In order to obtain the selection parameters of the large-scale radioactive waste liquid storage tank stubborn sediment retrieval device, Solidworks was used to establish a three-dimensional solid model,and EDEM software was used to carry out discrete element simulation analysis of the rotary tiller used for breaking the salt cake layer in the device; ANSYS software was used to carry out finite element simulation analysis of different suction force and shape of suction port during the cleaning process; ANSYS software was used to check the strength of the main force-bearing parts to be used. The relationship between the average force and time of the rotary tiller was obtained, and the maximum force value of 330 N, the best suction force value of 19 kPa and the best shape of the suction port were obtained. The main force components did not produce obvious deformation in the simulation analysis. It provided technical support for field verification experiments of devices.