In the present study, the effects of longitudinal strips on the stall delay and modifications flow for a low Reynolds number airfoil (SD7003) are experimentally investigated. The Reynolds number considered is Re = 6.0×10⁴ based on the chord length and freestream velocity. We measure the drag and lift forces on the airfoil by varying the angle of attack from α = 0° to 16° with and without the strips. Without strip, stall occurs at α = 11°. On the other hand, with strips the stall is delayed to α = 12°. To understand the mechanism responsible for the stall delay modification, we conduct a digital particle image velocimetry (DPIV) and surface oil visualization at high angles of attack where the lift is significantly enhanced by the strips. The streamwise vortices are generated at the strip edge, inducing downwash motion above the strip, supplying additional momentum to the surface, and resulting in stall delay.