Abstract: The vibration of the reactor core barrel reflects the vibration condition and equipment stability of the core barrel and corresponding reactor internals. This paper mainly focuses on the vibration characteristics of the core barrel shell mode with neutron noise technique and time-frequency signal analysis, and the change trend of shell mode characteristic quantities are obtained. The result shows that the vibration frequency of the core barrel shell mode has a decreasing trend within each fuel cycle and the vibration frequency would be recovered to the initial vibration frequency of the beginning of the last fuel cycle. The research of this paper contributes to further understanding of the vibration characteristic quantities of the core barrel shell mode and its causes of formation in multi-fuel cycles. The study results lay the foundation for early fault diagnosis for the core barrel.