Since distributed propulsion wing-body fusion (BWB) UAV has remarkable comprehensive performance and is the development trend of aircraft in the future aviation field, it is of great fundamental significance to analyze the aerodynamic characteristics of distributed BWB layout UAV for distributed BWB layout design. This paper uses computational fluid dynamics (CFD) numerical simulation to solve Reynolds mean Navier-Stokes (RANS) equation by using mixed grid technology and k-ω SST turbulence model. The effects of parameters such as with/without power, spanning position of culverts and culvert spacing on aerodynamics of the whole aircraft under cruising condition are studied. The results show that under the same working conditions, distributed power can improve the aerodynamic characteristics of the whole aircraft, and the outer wing segment is the main way to provide lift. The reasonable spacing of the culvert fans can produce a better induced lift effect, which shows that the lift coefficient of the whole engine first increases with the increase of the culvert spacing and then almost stays the same at a small Angle of attack. At high Angle of attack, the lift coefficient of the whole engine increases gradually with the increase of passage spacing, and its maximum increment is 9.3%. The above research and analysis of such aircraft have certain reference value for the aerodynamic layout design of distributed propulsion BWB UAV.