A 2 DOF model with the coupling of vertical and torsional motions is considered to study galloping of bundle conductors in this paper. By using the averaging method and the Routh-Hurwitz criteria, the motion equations are solved to discuss the stability of the trivial solution and find the influence of system parameters such as ice thickness, initial tension, vertical damping ratio and mass of unit length on the critical wind velocity. Based on some assumed condition, the calculation methods for the equivalent parameters of the bundle conductor are proposed to build the relations between ice thickness and the aerodynamics forces. Finally, the influence of wind velocity, ice thickness, initial tension, vertical damping ratio and mass of unit length on the amplitude of galloping is investigated.