Abstract: As the high-speed train runs, the auxiliary equipment of the vehicle is susceptible to fatigue damage due to complex vibrations and other effects.Therefore, the suspension water tank structure suspended on a CRH-type car body is taken as the research object, the load characteristics and service life of the structure are investigated when it is filled with liquid.The joint stress of the structure under the combined action of multi-directional vibration excitation and liquid sloshing pressure is calculated through the fluid-structure coupling numerical simulation.The fatigue life of the base material and welds in the hoisting water tank structure is predicted using the time-domain method, and the results are assessed according to the relevant railway standard GB/T 21563-2018:Railway applications-rolling stock equipment-shock and vibration tests.The results indicate that the first location offatigue failure in the suspension water tank structure location at the welding joint between the middle lifting lug of the hanging beam and the ribbed plate, and the minimum lifespanis 4.76×10⁸ s, which is much higher than 5.4×10⁴ s of the standard rating.It is concluded that the suspension water tank structure can meet the service requirements.