Based on the principle of similarity, a reduced-scale modeling test method for dynamic responses of twin-bundle conductor lines after ice-shedding is proposed. The simulation of ice-accretion and ice-shedding on sub-conductors of bundled conductors was achieved. A reduced-scale modeling test platform for dynamic responses of twin-bundle conductors after ice-shedding was established, which can be used to measure the in-plane, out-of-plane and torsional motions of the conductor after ice-shedding, and the time histories of conductor tension and the longitudinal, vertical, and horizontal components of reaction force at hanging points. Reduced-scale modeling tests were conducted for a typical twin-bundle conductor line, including partial ice-shedding and unzipping ice-shedding from a single sub-conductor, and asynchronous ice-shedding from the two sub-conductors. The variations of jumping height, lateral swing, torsion angle and tension of the conductor, and the reaction force at the hanging point versus time were measured. The proposed method provides an important means for deicing design and artificial ice-shedding research of bundle conductor transmission lines.