In order to improve the take-off and landing performance of civil transport aircraft, it is necessary to control the flow separation on the suction surface of the wing. The vortex generator is a simple passive flow control technology that has potential positive benefits for delaying the separation of the fluid boundary layer and improving the take-off and landing performance of the aircraft. Research on rectangular vortex generators was carried out through civil transport aircraft model wind tunnel tests. The rectangular vortex generator was installed near the leading edge of the inner wing of the wing. The test used smoke flow technology, fluorescent tuft technology and PIV particle image velocity measurement technology. Through smoke flow experiments and fluorescent tuft experiments, the conclusion that rectangular vortex generators can improve the separation of the inner wing downstream area of the wing was qualitatively captured; Through the PIV particle image velocimetry experiment, we quantitatively obtained a pattern of the use of a rectangular vortex generator at a designated station downstream of the inner wing of the wing, which can force the separation flow in the separation area to become an airfoil-attached flow again. Based on the test results, the rectangular vortex generator can significantly improve the low-speed characteristics of civil aircraft.