Abstract: To keep accuracy of the effects of liquid sloshing convective, impulsive and structural responses of reactor vessel, the similarity of gravity, inertial forces, elastic forces and strains should be ensured during seismic tests. The vibration equations of solid structure, dynamic equations of incompressible Newtonian fluid, boundary conditions of fluid-solid interface and linear liquid sloshing dynamic equations in annular cylinder domain were analyzed. Based upon dimensional method, the dynamic similitude laws for seismic responses of reactor vessel and reactor internals was derived considering liquid sloshing effect. The scaled models of reactor vessel, reactor internals and liquid with free surfaces in the reactor vessel were established according to proposed similitude laws. The modal analysis and response spectrum analysis were carried out on the prototype and scaled models based finite volume method. The frequency and height of liquid sloshing, hydrodynamic pressure and overturning moment caused by hydrodynamic pressure were obtained. The results show that proposed dynamic similitude laws are of great reasonableness and accuracy, and then could be applied in seismic tests of the scaled reactor vessel and its internals structures.