To study the seismic response of floating roof storage tank with the base isolation,the floating roof is assumed as a homogeneous rigid circular plate,the vibration form of wave height is assumed as linear distribu-tion along the radius.By the velocity potential theory,the velocity potential function of the liquid movement and the expression of base shear and overturning moment are established and by the plate vibration theory and energy principle,the motion equation for the floating roof and the motion equation for the tank system are pres-ented,respectively.With the time history analysis,the seismic responses for the isolated floating roof storage tanks are studied.The numerical results show that the fundamental frequency of isolation is applicable to be 2-3 rad/s,while the damping ratio of isolation is 0.1.The damping rates ofⅠ,Ⅱsite are better than those of Ⅲ,Ⅳsite.The effects of different sites on wave height are different,and the ratio of height to diameter has little effect on the seismic response of the isolated floating roof storage tanks.