As a new type structure, the dynamic behavior of the irregular concrete filled steel tube arch bridge under moving vehicles was rarely studied. In this paper, taking the bridge crossing Yitong river in Changchun of China as an example, the dynamic response of the bridge is investigated by the self-compiling vehicle-bridge coupled vibration analysis program. The surface roughness and vehicle speed are considered in the analysis. The results show that impact factors of the bridge increase as surface roughness deteriorated; the impact factor varies obviously for the different component; the tension impact factor of the short suspender is larger than that of long ones; damping ratio of structure has little effect on the impact factors. The research conclusions can be referred in the design and assessment for the similar bridges.