Abstract: In order to explore the correlation between the unsteady flow structures and pressure pulsation in high-temperature molten salt pump for concentrating solar power（ CSP） plants,a model of pump and the storage tank was constructed,the numerical calculation based on the RNG k-ε turbulence model was carried out,and the characteristics of the pressure pulsation spectrum and the evolution of the vortex structure in different operating conditions were analyzed. The results show that rotor/stator interaction（ RSI） stimulates blade passing frequency（ fBPF） and diffuser passing frequency（ fDPF） signals,which are dominated in pressure pulsation spectra. The pressure pulsation amplitude varies with the operating conditions and the positions in the pump. There are multiple evolutions of unsteady vortex structures captured by Q-criterion,respectively,including trailing edge shedding vortex（ 2 fR-3 fR）,suction surface shedding vortex（ 3 fR） and the like. Correlation analysis shows that the pressure pulsation amplitude of the vortex evolution region increases significantly,whose frequency is consistent with the vortex shedding frequency. The conclusion is that pressure pulsation is closely related to vortex structure evolution. The results provide a basis for revealing the unsteady flow excitation characteristics and hydraulic optimization in molten salt pump.