Aircraft incidents frequently occur during the low-speed phases of takeoff and landing, where the proper deployment of lift-enhancing devices is crucial for augmenting flight safety. This study evaluates the impact of various lift devices on the aerodynamic performance of domestic wide-body airliners during these critical phases. A fully structured body-fitted grid is adopted to discretize the large wide-body aircraft into hundreds of millions of cells, and the Reynolds-averaged turbulence model is applied to conduct numerical simulation on aerodynamic performance. The reliability of the numerical simulation method is verified by comparing with the wind tunnel experimental results. Four typical cases of Ma=0.2, incoming flow angle of 0°, 5°, 10° and 15° are selected, and the effects of lift devices such as flaps, slats, spoilers, etc. on the overall aerodynamic performance of the aircraft are analyzed. The study’s findings reveal that the fully structured grid employed herein accurately captures the three-dimensional mean flow field characteristics under various lift device configurations. Within an angle of attack range from 0° to 10°, the utilization of spoilers can reduce the aircraft’s lift coefficient and increase the drag coefficient during the landing phase. Furthermore, between 0° and 15° angles of attack, the application of slats and flaps provides additional lift, thereby enhancing takeoff performance and stall characteristics.