With the development of vertical take-off and landing (VTOL) vehicles, urban air mobility (UAM) is emerging as a future solution to alleviate traffic congestion in megacities. In urban area, complex terrain, building-induced turbulence wake and wind shear may significantly perturb eVTOL aerodynamic performance. furthermore, to effectively reduce the congestion, the vertiports must be located in central urban areas, thereby exposing VTOLs to the strong influence of turbulence wake generated by tall buildings during take-off and landing. This paper conducts a numerical study on the coupled flow field between a lift-plus-cruise eVTOL and the wake of the tall buildings by using the Detached Eddy Simulation (DES) method. The hovering and the landing of the eVTOL under the different influence of the wake were numerically simulated. Firstly, the aerodynamic interference of building wake on the lift propellers of the lift-plus-cruise eVTOL during hovering in different regions of the wake was investigated. Secondly, the numerical simulations were conducted on the coupled flow field of the building wake and a eVTOL under different free-stream conditions, and the effects of wake on the aerodynamic perfoemance of the eVTOL under various wind directions were investigated. Finally, the the landing process of the eVTOL was numericall smilated to study the influnece of the buliding wake to the eVTOL.The results show that the wake may significantly effect the lift and torque of the eVTOL, thus leading to lift fluctuations and reduced controllability.