Deep excavation in soft clay often brings soil stress disturbance and soil deformation, which would bring differential settlement and structural cracks. It probably brings safety problems to adjacent underground tunnels. Therefore, it is necessary to predict tunnel displacement induced by excavation for tunnel’s security. A new method was proposed to estimate the heave of underlying tunnel induced by adjacent excavation verified by field measurements. The soil deformation by excavated soil gravity was analyzed by application of Boussinesq solution. The soil deformation by tunnel surface pressure was analyzed by Mindlin solution. The tunnel was assumed to be an elastic beam on foundation to simulate the tunnel, in which interaction analysis of tunnel and soil was employed. In consideration of rheologic soil， Viscoelastic model was employed to analyze soil nonlinear displacement with time in soft clay. Tunnel displacements were discussed by different excavation cases. A case study showed a good agreement between the results from the prediction and the measurement.