Large turbine–generator foundation can reduce the vibration in an effective way by mounting vibration isolating springs when the equipments are operating. But under strong earthquake actions, the research of seismic behavior is presently limited to theoretical calculation and there are no test results or observation data. In this paper, 1:10 spring vibration isolating foundation model is made to carry out a pseudo–dynamic seismic test. This paper also analyzes the deform distribution of column and spring of turbine–generator foundation under horizontal earthquake actions. The test results show that because of the spring of column top, deform distribution of foundation has changed; column top displacement of each column is different; spring can regulate the internal force of the column and these springs are also able to resist horizontal earthquake action when they are reducing the vibration of the equipments.