Abstract: In order to simulate the effect of the liquid sloshing of fast reactor on the main container, a scaling method for seismic test of fast reactor vessel considering fluid structure interaction effect was created in this paper. It not only ensures the acceleration similarity ratio is strictly 1, but also ensures the mass ratio of fluid to structure is the same as that of the original reactor. On the basis of the method, two scaled-models with the scale of 1∶25 (large) and 1∶50 (small) for the prototype of fast reactor were designed respectively. In order to verify the validity of the above method, the numerical simulations of the two models were carried out, and the simulation results of the large model and the small model were compared. The comparison results show that the ratio of vibration motion response parameters of the large and small models meets the derived theoretical criteria. The above simulation method is proved to be valid by numerical experiments. This scaling method can provide theoretical basis for seismic test of fast reactor vessel.