<p>With the development of urban construction, viaducts have become a key solution to traffic issues and an integral part of urban space. The large number of viaducts have created many under-bridge spaces whose landscapes have a great impact on the public’s psychology and behavior. Different travel modes offer varying perspectives, speeds, and spatial perceptions, influencing the public’s visual preference for under-bridge space landscapes. At present, most existing studies on landscape preference are conducted from the perspective of pedestrians, and quite little has been done about how the public’s landscape preference for the under-bridge space varies in terms of different travel modes. This study is the first to compare travel mode preferences in under-bridge spaces, with the landscape under the viaduct of six representative cities in China as the research object, this study set five landscape features, namely, plant coverage, number of plant species, plant vertical structure, number of plant colors, and vertical greening of bridge columns. Photo stimulation method was used to conduct experiments with the public in the three travel modes, namely, walking, cycling, and car driving. On this basis, this study explored the influence of the five landscape features on the visual preference assessment rendered by the public in different travel modes. The results show that the above five landscape features all exert an important impact on the public’s visual preference assessment. The landscape with high plant coverage, 3–4 plant species, moderate vertical structure of plants, 3–4 plant colors and bridge columns with vertical greening is more popular among the public. The public in different travel modes renders different visual preferences for the under-bridge space landscape. This study provides valuable help for the under-bridge space landscape design.</p>