This paper is aimed at investigating galloping behavior of iced catenary. The nonlinear motion equations of the iced catenary are established where the cross-section shape of the iced contact wire differs from the one of the iced messenger wire. The galloping characteristics of the iced catenary and the effects of the icing thickness are studied. The results indicate that dominant frequency, intensity of beat vibration, track and maximum vertical/lateral displacements of each span of the iced catenary may be different but are symmetric with respect to the center of the catenary. The geometric nonlinearity of the iced catenary makes the system more stable. Compared with the contact wire, variation of the icing thickness of the messenger wire makes nonlinear critical wind speed of the iced catenary vary more greatly. The larger the icing thickness, the smaller the linear critical wind speed, but there is a basic unstable area that is almost independent of the icing thickness.