Abstract: The application of surface structure drag reduction technology is crucial for optimizing the aerodynamic performance of large passenger aircraft. Among these, passive drag reduction structures have become a current research hotspot due to their straightforward structural design and reliable drag reduction performance. To address the limitations of single passive structures in improving wing aerodynamic performance, this study systematically investigates the synergistic control effect of vortex generator (VG) and riblet structures on near-wall flow over a wing at high angles of attack. Using the NACA 23021 airfoil, the wind tunnel and the particle image velocimetry are conducted to compare the flow characteristics and drag distribution of four surfaces—smooth, VG, riblet, and VG-riblet—under high angles of attack near stall conditions. Results show that the VG configuration enhances momentum exchange and suppresses flow separation by inducing streamwise vortices, but it increases the average skin friction coefficient by 150% compared to the smooth airfoil. In contrast, the VG-riblet composite structure demonstrates significant synergistic drag reduction. It reduces skin friction by 60% compared to the VG case and achieves an overall drag reduction rate 3.8% higher than the smooth airfoil. Mechanism analysis reveals that VG strengthen Q2 (ejection) and Q4 (sweep) turbulent burst events, promoting the generation of large-scale vortices. Riblets effectively suppress the intensity and extent of near-wall Q2 events and reduce Reynolds stress through micro-vortex dissipation. The two components act synergistically to integrate effects of "enhanced adhesion" and "turbulence suppression" in a complementary way, thus offering a novel direction for high-efficiency drag reduction of aircraft.