A numerical simulation analysis method was studied for the flexible securing system of heavy-duty packaging. The CABLE280 element of workbench was used to simulate the flexible cable structure in the bundling system, and the simulation ability of this element in the geometric shape of the bundling object, the pre tension force of the rope, and the relaxation characteristics of the rope were explored. The influence of the geometric shape of the tied object on the accuracy of rope simulation was analyzed. The simulation analysis experiment on the relaxation characteristics of flexible cables was designed and the simulation ability of the CABLE280 element in flexible cables was studied. The analysis results indicate that the CABLE280 element can simulate the pre stress and relaxation characteristics of ropes. By geometrically processing the edge structure of the tied object and applying pre stress, CABLE280 can be used to simulate the flexible cable structure of packaging systems.