Abstract: A large number of transportation infrastructures along the river are built on liquefiable valley sites. Earthquake-induced site liquefaction is one important cause of severe earthquake damage to riverside buildings. Valleys show a significant topography effect which means valleys of different sizes present different seismic response. It is of great significance to conduct systematic investigation on the correlation between topography effect and site liquefaction. In this paper, we employed OpenSees to analyze 5 liquefiable site models with different valley depths to explore the influence of valley depth changes on pore water pressure. It is found that during shaking, there is a significant correlation between the valley depth parameter and the pore water pressure of saturated sand within a certain depth range from the valley bottom. As the valley becomes deeper and free water body emerges, the shear shrinkage on the shallow area of the valley bottom gradually weakens, the dilatancy gradually strengthens, and the instantaneous liquefaction zone gradually migrates from the shallow surface area of the slope to deeper. In addition, compared with the saturated sand near the midpoint of the valley bottom, the correlation between pore water pressure of saturated sand near the slope toe and valley depth is more significant. The numerical modeling technology presented in this paper as well as the insights obtained in this investigation can provide some reference for the site selection of new riverside constructions and the design of site anti-liquefaction.