The integrated fast reactor combines the superheater into the steam generator (SG) to obtain a large SG, which greatly improves the structural size and flow velocity. As the pressure boundary of the secondary circuit, the heat transfer tubes of the SG play an important role in the heat transfer of the secondary circuit and the tertiary circuit, and its integrity is very important for the safe operation of the SG. Under the scouring action of transverse flow, the heat exchange tubes of SG cause the vibration of tube bundle, which leads to the wear, fatigue failure and even rupture of heat exchange tube. The flow-induced vibration (FIV) analysis is necessary to ensure its safety and reliability. The FIV of heat exchange tube bundles is mainly affected by the flow velocity of the flow field, the arrangement of the tube bundles and the supporting structure. There are three design criteria (National Standardization Administration of China in GB/T151—2014 China Standard Book Number, China Standards Publish-ing House, Beijing, 2015, [1]; National Standardization Administra-tion of China, GB/T151—2014 China Standard Book Number. China Standards Publishing House, Beijing, 2015, [2]; American So-ciety of Mechanical Engineers in ASME N-1300 Boiler and Pres-sure Vessel Code, American society of mechanical engineers, USA, 2007, [3]) which can be used to analyze the FIV of heat exchanger equipment, but the applicability of the calculation method in the design criteria to the fast reactor steam generator with liquid sodium as the external flow field and water as the internal medium of the heat exchanger tube needs to be evaluated. Based on the design criteria, this paper analyzes the turbulence buffeting and Karman vortex of the large steam generator of the integrated fast reactor, studies the flow velocity analysis method, and verifies and corrects the existing calculation model with the experimental data, and finally obtains the FIV analysis method suitable for the large SG of the integrated fast reactor.