A numerical study was performed to explore the unsteady interaction between the upstream propeller and the downstream swirl recovery vane(SRV) by transient simulations. Much larger fluctuations of thrust coefficient were observed on the vane, which indicates that the variations of the total efficiency depend mainly on the working performance of the stator. The harmonic loads of the decomposed unsteady blade-surface pressures show that the stator experiences about ten times higher of unsteadiness compared with the rotor. Notable changes appear at the vane leading edge due to the potential disturbance as well as the sweeping effects from the wake of the upstream propeller, whereas more significant unsteadiness occurs at the stator tip region as a result of the interaction between the rotor/stator tip vortices. The visualization of vortex structures addresses that the rotor tip vortex has a dominant effect on the stator tip vortex since the latter one starts right at the impingement location on the vane top in this configuration. Furthermore,a longer and a shorter SRV were investigated based on the original case to explore different interaction patterns for the rotor/stator tip vortices. Weaker effects have been observed as expected. A numerical study was performed to explore the unsteady interaction between the upstream propeller and the downstream swirl recovery vane (SRV) by transient simulations. Much larger fluctuations of thrust coefficient were observed on the vane, which indicates that the variations of the total efficiency depend mainly on the working performance of the stator. The harmonic loads of the decomposed unsteady blade-surface doses show that the stator experiences about ten times higher of unsteadiness compared with the rotor. Notable changes appear at the vane leading edge due to the potential disturbance as well as the sweeping effects from the wake of the upstream propeller, and more more significant unsteadiness occurs at the stator tip region as a result of the interaction between the rotor / stator tip vortices. The visualization of vortex structures addresses that the rotor tip vortex has a dominant effect on the stator tip vortex since the latter one start right at the impingement locat ion, and the shorter SRV were investigated based on the original case to explore different interaction patterns for the rotor / stator tip vortices. Weaker effects have been observed as expected.