In the investigation,by using the finite element ( FE) analysis software ANSYS,a FE model of the UHV electrical equipment with the flexible bus connection is constructed,so as to reveal the seismic coupling effect of the UHV electrical equipment and the flexible bus.Then,the correctness of the constructed FE model is verified by the shaking table tests.Moreover,a configuration function and a sag formula of the flexible bus considering stiffness are deduced,and the factors influencing the seismic coupling effect of the UHV electrical equipment with the flexible bus connection,namely,the bus-redundancy,the frequency ratio of the equipment,and the geometrical size and elastic modulus of the flexible bus,are analyzed.The calculation results show that the existence of the stiffness of the flexible bus enhances the seismic coupling effect between the flexible bus and the UHV electrical equipment,which can further? increase the earthquake response of the UHV electrical equipment,and that,smaller redundancy,greater geometrical size and higher elastic modulus of the flexible bus as well as bigger difference in the frequencies of the UHV electrical equipment will enhance the seismic coupling effect.