In order to solve the practical problem of the conflicting between the shortage of land and the power consumption requirements, the substations used to be set in a separate area are built as a module attached to or put into the other comprehensive buildings in more and more area. This attached build substation equipment will cause vibrations in the structure of multi-floor, not only reduces the device's dynamic accuracy and performance，but also the reduces the floor vibration comfort. Based on the analysis of national building codes of the basic provisions on the vibration comfort index, the finite element models of the whole structure with an attached substation equipment with and without the vibration isolator were established to obtain the dynamic responses in the exciting of the machines. Through the vibration analysis of the each model, the calculated results and the specification limits are compared to determine the comfort of the building with the attached substations and isolation effect.