Abstract: The flow-induced vibration characteristic of a new nuclear reactor was analyzed in this paper by performing dynamic test and numerical calculation. A 1/2 scaled-down model of a new designed nuclear reactor was manufactured for performing the dynamic test with the hydrodynamics simulation system at the 100% operation condition. And the dynamical responses of core barrel and secondary core support structure were measured in the test. Based on the results of the dynamic test, a three-dimensional finite element model of the reactor internals for the numerical analysis was constructed to obtain the max strains and stresses of core barrel and secondary core support structure at the 100% operation condition.