The dynamic response of reservoir-gravity dam-foundation interaction is calculated using the scaled boundary finite element method (SBFEM) in frequency domain. The transmitting boundary for the structure-unbounded foundation interaction analysis in frequency domain is used. The lingering effect of the unbounded foundation on the earthquake response of the dam is analyzed. Characteristics of several approximate models developed in the literature are investigated and compared. The results show that the dynamic stress modeled by mass-less foundation overestimate the earthquake response of the dam and the maximum stress considering the effect of the lingering effect is more than that of no lingering effect.