Abstract: According to the traveling wave effect on the seismic response of large span structure,this paper took a main span of 260 meters of half-through steel arch bridge as an example and used large mass method to realize multi-support excitation of traveling wave effect.Through selecting five sections,study on the traveling wave effect of seismic response of bridge were made under diverse phase difference,and the comparative analysis with result of uniform excitation were carried out.The calculation showed that the former seismic response was greater than the latter's and the peak of vertical displacement,axial force and transverse moment was respectively 10.9,6.5 and 5.1 times of the latter's when the phase difference was 5.2s.With decrease of the phase difference,the displacement and internal force of the structure present decreasing trend when considering the traveling wave effect.Therefore,the traveling wave effect should be considered in the aseismic design of long-span Bridges.