Abstract:in the process of urban construction, tunnel excavation will pose a great threat to the adjacent existing pile under high-speed railway. Isolation pile hitted between the tunnel and high iron pile foundation pile can effectively reduce the influence of the shield driving to adjacent pile foundation. In the field of the study of interaction of piles and soil, Winkler foundation model and Pasternak foundation model have been widely used. Based on these two foundation models, this paper using the finite difference method by Maple mathematical software analyses a practical engineering case, the calculated results in accordance with existing engineering monitoring data, then further analyses the isolation pile of various parameters on the horizontal displacement of the pile under high-speed railway. The results show that Pasternak foundation model is more accurate than Winkler foundation model when the elastic modulus of isolation pile is smaller. With the increase of isolated pile diameter, the horizontal displacement of pile foundation will decrease significantly. The horizontal displacement of HSR pile foundation can be reduced by reducing the horizontal distance between the isolated pile and the tunnel center line on the condition that the parameters of isolated pile remain unchanged.