In order to optimize the low-speed characteristics of the high-lift configuration of civil transport aircraft and enhance the take-off and landing performance of the aircraft, it is necessary to control the flow separation of the wings. Through the wind tunnel test, the research on the selection of two passive control technologies, the wing-body fairing and outboard nacelle strake, was carried out. The best combination scheme that can optimize the low-speed characteristics has been found, and the area where the flow separation is suppressed by the optimization method has been presented through the flow visualization test. Under normal pressure conditions, the maximum lift coefficient is increased by about 7% under the effect of the optimal wing-body fairing, and the stall angle of attack is delayed by about 3°. Under the combination effect of wing-body fairing and outboard nacelle strake, the maximum lift coefficient is increased by about 9%. Under pressurized conditions, the combination of the optimal wing-body fairing and the outboard nacelle strake under the Reynolds number effect increases the maximum lift coefficient by about 5% on the basis of the normal pressure test results. The angle of attack is delayed by about 1.7°.