Abstract: Responses of the radiation vessel assembly of China Experimental Fast Reactor to flow-induced vibration were measured by DASP-V10 vibration system in a thermal hydraulic test facility. The first five intrinsic frequencies and mode shapes of assembly were obtained by the test. Vibration and dynamic strains responses were obtained during the dynamic tests which were operated in the rated flow of 0.6 m³/h and 120% of the rated flow. The flow-induced vibration test was operated to follow the results of the test measurements for intrinsic vibration characteristics. Results of the two tests give the reason why the resonance vibration occurrs and explain its effect to the assembly based on vibration mechanics.