Abstract: The flow induced vibration (FIV) problems affect the safe operation of reactor. It is paid attention to by the nuclear engineering for a long time. The pump-induced pressure pulsation is an important excitation source of FIV, which will lead to periodic vibration of reactor core barrel (CB) and other components. It may cause resonance and have the adverse impact on the fatigue life of structure. In order to study the vibration of core barrel (CB) of newly designed Hualong No.1 reactor under pump-induced pressure pulsation, the finite element model of the CB was established and the dynamic response characteristics under pump-induced pressure pulsation were analyzed. Considering the turbulence excitation, the overall response of the CB under the FIV was evaluated. The stress analysis shows that the maximum flow induced stress intensity at each position of the CB is less than the fatigue stress limit, and the structure is safe. However, for the newly designed reactor or the change of the main pump in the reactor coolant system, the pump induced vibration of the reactor system should be paid attention to.