Abstract: According to the evaluation of effect of dewatering of excavation of Huqiu Wedding Mall in Suzhou on nearby Shanghai-Nanjing Railway, on the basis of the Darcy's law and the Dupuit assumption, some computing ideas on changes of groundwater levels caused by dewatering of excavations near the piers of piers of operating high-speed railways, considering different degrees of failure cases of closed cut-off curtains in excavations. The pier settlement of operating high-speed railway and change of safety factor caused by the dewatering of excavations are analyzed. The results show that, under certain assumptions, the dewatering of excavations will cause the nonlinear in crease of the neutral point of the bridge and pier settlement growth changing. The safety factor of the pile foundation is reduced, and the piers of high-speed rail ways are sensitive to change of groundwater.