In order to meet the functional characteristics of the flying wall crawler, the structure of the flying wall crawler is such that the four rotors are not in the same plane but in a longitudinal arrangement when in flight. The CFD (computational fluid dynamics) simulation of the single-rotor flow field was carried out to verify its reliability. On the basis of these simulations, aerodynamic simulations were carried out for different horizontal spacing, different vertical spacing and different rotational speeds of the longitudinal double rotor. The results were then analysed to determine the effect of the horizontal and vertical spacing and the rotational speed on the aerodynamic characteristics of the front and rear rotor blades and the whole system. The simulation results show that the transverse pitch has a large aerodynamic interference between the longitudinal rotor blades, while the axial pitch is relatively small and the degree of interference is related to the rotational speed. It is clear that the conclusions can provide a basis for the rotor layout, rotational speed and feasibility of flying wall climbing robots.