In this paper, the seismic response of long-span tensioning truss structures on soft soil foundation is analyzed, and the influence of traveling wave excitation on the relative displacement response of mid-span joints and the normal stress response of structural rods considering soil-structure interaction is studied. According to the equivalent linearization method based on linear wave method in frequency domain, a large-span tensioning truss structure model considering soil-structure interaction is established, and the seismic response under traveling wave excitation and uniform excitation is compared. According to the requirement of seismic code, multi-dimensional input of inversion bedrock ground motion is carried out. The peak relative displacement response of the mid-span nodes under traveling wave excitation is 74%–92% of that under uniform excitation. The maximum normal stress response of the mid-span member under traveling wave excitation is 1.12–1.36 times that under uniform excitation. The results show that traveling wave excitation can reduce the relative displacement response of mid-span nodes. Traveling wave excitation can reduce the normal stress response of mid-span members.