The construction and development stages of the underground walkway in the railway passenger transport hub are sorted out. The classification of the underground walkway is studied. The form mode and applicability of the underground walkway are analyzed. According to the study results, some suggestions are put forward for the planning of the underground walkway in the reconstruction and expansion of North Suzhou Railway Station. Its achievements can provide the reference for the establishment of a perfect underground walking traffic system, the realization of green traffic development and the improvement of the overall spatial quality of the city in the railway passenger transport hub.