Ice accretion on catenary cantilever assemblies makes ice removal difficult and complicates the determination of effective de-icing paths for complex tubular components. To address this issue, a mechanical de-icing method based on the impact of a cylindrical polytetrafluoroethylene (PTFE) rod is proposed. A finite element model of an iced German-type aluminum alloy cantilever assembly was established, including the horizontal arm, inclined arm, cantilever support, and positioning tube. The model was used to analyze local compressive damage, crack propagation, and ice–substrate interfacial debonding under impact loading. Based on the single-impact de-icing range of each component, an axial impact spacing strategy with a 50% overlap ratio was adopted, and an alternating upper-lower impact path was planned. Full-diameter axially segmented tests and overall path-based de-icing tests were then conducted to validate the proposed method. The results showed that the relative error in de-icing area between the simulation and experiments ranged from 2.63% to 14.54%, which was less than 15%. Under the planned path, the average de-icing rate of the cantilever assembly reached approximately 79.3%. The results indicate that the cylindrical PTFE rod impact method can effectively fracture and detach ice accretion from catenary cantilever assemblies, and that the proposed path planning method provides a reference for end-effector design and operation path generation in automated catenary cantilever de-icing equipment.